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Question Stats: 73% (02:52) correct 27% (02:49) wrong based on 794 sessions

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On a certain day, a bakery produced a batch of rolls at a total production cost of $300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls? A.$ 150

B. $144 C.$ 132

D. $108 E.$ 90

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Senior SC Moderator V
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carcass wrote:
On a certain day, a bakery produced a batch of rolls at a total production cost of $300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls? A.$ 150

B. $144 C.$ 132

D. $108 E.$ 90

Method I: assign a value to the total number of rolls

Because all the rolls are sold, and because they are all sold at equal prices on their respective days, we can use any number of rolls we want to calculate
Profit as (Total Revenue - Total Cost).

The profit is the same for 300 rolls that cost $300 as it is for 30 rolls that cost$300.

Let # of rolls = 30
Cost per roll = $10 Day 1: $$\frac{4}{5}$$ of 30, or 24 rolls, are sold at 50 percent above cost --> Day 1, PRICE: 50% above cost is (1.5 *$10) = $15 each Day 1, Total Revenue: (24 *$15) = $360 Day 2: remaining 6 rolls are sold at 80 percent of Day 1's price (of$15) -->
Day 2's price is (.8 * $15)=$12 each

Day 2, Total Revenue: (6 * $12) =$72

Total Revenue for both days: ($360 +$72) = $432 (TR - TC) = PROFIT PROFIT = ($432 - $300) =$132

Method II - Algebra

$$xy = 300$$ = Total cost, where $$x$$ is unit cost of rolls and $$y$$ is # of rolls

Day 1 = $$\frac{4}{5}y * \frac{3}{2}x = \frac{6}{5}xy$$

Day 2 = $$\frac{1}{5}y * (\frac{4}{5}*\frac{3}{2})x$$

$$= (\frac{1}{5}y*\frac{12}{10}x)=\frac{12}{50}xy=\frac{6}{25}xy$$

Day 1 + Day 2: $$(\frac{6}{5}xy + \frac{6}{25}xy)= \frac{36}{25}xy$$

$$xy = 300$$, so
Total revenue = $$(\frac{36}{25})(300) = 432$$

Total cost = $$300$$
Profit = (TR - TC)
Profit = $$132$$

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GMAT 1: 670 Q49 V33 On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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My approach:

Let x is the number of rolls made. Average cost is 300/x.

4/5 of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll,
so first day revenue = $$\frac{4x}{5}$$ x $$\frac{300}{x}$$ x 150%

The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before,
so second day revenue = $$\frac{x}{5}$$ x $$\frac{300}{x}$$ x 150% x 80%

Total Revenue = $$\frac{4x}{5}$$ x $$\frac{300}{x}$$ x 150% + $$\frac{x}{5}$$ x $$\frac{300}{x}$$ x 150% x 80%
= 432 (x will be canceled out)

Cost = 300, so Profit = 432-300 = 132
General Discussion
Target Test Prep Representative G
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Re: On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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carcass wrote:
On a certain day, a bakery produced a batch of rolls at a total production cost of $300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls? A.$ 150

B. $144 C.$ 132

D. $108 E.$ 90

We can let the production cost per roll = x and the total number of rolls = t.

On the same day the rolls were made, we are given that (4/5)t rolls were sold at 1.5x each. So the revenue was (1.5x)(4/5)t = 1.2xt

On the following day, we are given that (1/5)t of the rolls were sold for 0.8(1.5x) = 1.2x each. So the revenue was 1.2x(1/5)t = 0.24xt.

Since the production cost was 300:

300 = xt

So,

Profit = (1.2xt + 0.24xt) - xt

profit = (1.44xt) - xt

profit = 1.44(300) - 300 = 132 dollars.

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GMAT 1: 730 Q50 V38 On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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Let no. of rolls = n
production cost of each roll =p

Given total production cost = n*p =300

Now 1st day : 4/5 no. of rolls were sold at 50% more than production price:
so selling price = (1+50/100)p = 1.5p

so revenue on 1st day = (4/5 *n) *(1.5p) = 1.2 np

now second day: remaining rolls ie 1/5th of rolls sold at 20% less than previous day price :
so selling price = (1-20/100)(1.5p) = 0.8 *1.5p

so revenue on 2nd day = (1/5 *n) *(0.8 * 1.5p) = 0.24 np

Total revenue = 1.2np +0.24np = 1.44np
as np=300
Total revenue = 1.44* 300 = 432

Profit = Revenue - production cost = 432-300 = 132

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Re: On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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Can anyone tell me what is wrong with my calculation? carcass

Assume batch of rolls =5
Cost per roll = $300/5=$60

First day sales : 4/5*5*$60*1.5 =$360
Second day sales : 1/5*5*$60*0.8 =$48
Total sales = $408 Profit =$408-$300 =$108
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GMAT 1: 670 Q49 V33 Re: On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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chid2 wrote:
Can anyone tell me what is wrong with my calculation? carcass

Assume batch of rolls =5
Cost per roll = $300/5=$60

First day sales : 4/5*5*$60*1.5 =$360
Second day sales : 1/5*5*$60*0.8 =$48
Total sales = $408 Profit =$408-$300 =$108

Hi,

The question stem said that "The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before"
So your calculation for second day sale should be 1/5*5*$60*1.5*0.8 = 72. Manager  B Joined: 21 Jun 2017 Posts: 82 Re: On a certain day, a bakery produced a batch of rolls at a total produc [#permalink] Show Tags 1 1 carcass wrote: On a certain day, a bakery produced a batch of rolls at a total production cost of$ 300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls?

A. $150 B.$ 144

C. $132 D.$ 108

E. $90 Since they never give you total amount of rolls produced, just make it 100 rolls, because 100 is an easy number to work with. Total cost =$300
Total rolls produced = 100
$3.00 per roll 50% of$3.00 is $4.50 4/5 of 100 is 80 80 x 4.50 =$360.00
20% of 4.50 = $.90 4.50 - .90 =$3.60
3.60 x 20 = $72.00$360.00 + $72.00 =$432.00
$432.00(revenue) -$300.00(cost) = $132.00 (Profit) Ans is (C) Manager  B Joined: 12 Nov 2016 Posts: 130 Concentration: Entrepreneurship, Finance GMAT 1: 620 Q36 V39 GMAT 2: 650 Q47 V33 On a certain day, a bakery produced a batch of rolls at a total produc [#permalink] Show Tags 3 2 I cant's understand why we can't just simply find the cost of goods sold at the first day = 240 (4/5=300) Then add a margin of 1.5, 240*1.5= 360 (sales) and get profit of the 1st day 360-240 = 120 Then why can't we simply apply 0.8 discount (20% off) to the gross margin for the 1st day of 1.5*0.8 and get 1.2 Applying to 1.2 to 60 (cost of goods sold of the 2nd day, which is found as 300*1/5) = 72 (sales) 72-60 = 12 and 120 + 12 = 132 Why do we need to imagine a number of units sold or write equations? Manager  G Joined: 06 Sep 2018 Posts: 173 Location: Pakistan Concentration: Finance, Operations GPA: 2.87 WE: Engineering (Other) Re: On a certain day, a bakery produced a batch of rolls at a total produc [#permalink] Show Tags 1 suppose there are $$100$$ roles in a batch Average price per role is$$=300/100=3$$ as $$4/5$$ of $$100$$ roles $$= 80 roles$$ $$80$$ roles sold at price $$1.5*3=4.5$$ total revenue out of $$80$$ roles$$=80*4.5=360$$ Now, remaining $$20$$ roles sold at price $$20%$$ less than previous day price $$(4.5)$$ So price per role for day 2 is $$= 0.8*4.5=3.6$$ Revenue out of $$20$$ roles on day 2 $$= 20*3.6=72$$ So total revenue of $$100$$ roles $$= 360+72=432$$ $$Profit=Revenue-Cost=432-300=132$$ Answer C _________________ Hitting Kudos is the best way of appreciation. Eric Thomas, "When you want to succeed as bad as you want to breathe, then you'll be successful." Manager  S Status: Don't Give Up! Joined: 15 Aug 2014 Posts: 95 Location: India Concentration: Operations, General Management GMAT Date: 04-25-2015 WE: Engineering (Manufacturing) Re: On a certain day, a bakery produced a batch of rolls at a total produc [#permalink] Show Tags JeffTargetTestPrep wrote: carcass wrote: On a certain day, a bakery produced a batch of rolls at a total production cost of$ 300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls?

A. $150 B.$ 144

C. $132 D.$ 108

E. $90 We can let the production cost per roll = x and the total number of rolls = t. On the same day the rolls were made, we are given that (4/5)t rolls were sold at 1.5x each. So the revenue was (1.5x)(4/5)t = 1.2xt On the following day, we are given that (1/5)t of the rolls were sold for 0.8(1.5x) = 1.2x each. So the revenue was 1.2x(1/5)t = 0.24xt. Since the production cost was 300: 300 = xt So, Profit = (1.2xt + 0.24xt) - xt profit = (1.44xt) - xt profit = 1.44(300) - 300 = 132 dollars. Answer: C Hi Jeff, What should be the time required for the calculation in this question? Just Checking where i am? _________________ - Sachin -If you like my explanation then please click "Kudos" Director  D Joined: 19 Oct 2018 Posts: 952 Location: India Re: On a certain day, a bakery produced a batch of rolls at a total produc [#permalink] Show Tags Profit on first day= 50% SP on 2nd day=450*0.8=360 Profit on second day= 20% 50........20 .......x...... 4............1 4*(50-x)=x-20 x=44 Net profit= 44*300/100=132 carcass wrote: On a certain day, a bakery produced a batch of rolls at a total production cost of$ 300. On that day, $$\frac{4}{5}$$ of the rolls in the batch were sold, each at a price that was 50 percent greater than the average (arithmetic mean) production cost per roll. The remaining rolls in the batch were sold the next day, each at a price that was 20 percent less than the price of the day before. What was the bakery's profit on this batch of rolls?

A. $150 B.$ 144

C. $132 D.$ 108

E. \$ 90
Intern  B
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Posts: 21
Re: On a certain day, a bakery produced a batch of rolls at a total produc  [#permalink]

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Let there be 100 rolls sold at a price of INR 300.
Thus, avg cost of rolls is INR3 on a certain day. That day, 4/5 ie. 80% of the rolls were sold at 50% higher price. Thus, there are 80 rolls sold at INR (3 (1.5)) = INR 4.5. Thus, money made that day is INR 360.
Next day remaining batch of 20 rolls were sold at a price that was 20 percent less than the price of the day before.
(Here is the trick in the Question. There are 2 selling price in the previous day -> 3 and 4.5. We of course need to take 4.5. I admit that i fell for the question trap, took 3 as the selling price and marked the answer as 108-> [360+(20*2.4)]-
20% less on INR 4.5 comes to INR 3.6. This we multiply with 20 to get money made the next day as 72. Thus, total money made on 2 days is 360 + 72 = 432. Thus, profit made is INR 132 (432-300) Re: On a certain day, a bakery produced a batch of rolls at a total produc   [#permalink] 14 Aug 2019, 18:18
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