Originally, the bill for Quon's meal wass $11.88, which included an 8%

Question

Originally, the bill for Quon's meal wass $11.88, which included an 8% tax on the cost of the meal. Quon presentend a discount coupon for 25% off the cost of his meal. Quon's final bill was the discounted cost of the meal plus the 8% tax on the discounted cost of the meal. How much was Quon's finall bill?

A. $8.91
B. $8.93
C. $9.13
D. $9.62
E. $11.63

A. $8.91
B. $8.93
C. $9.13
D. $9.62
E. $11.63

LucienH · Accepted Answer

Initial bill before tax = 11.88/0.92

untaxed discounted price = 0.75 * (11.88/0.92)

taxed discounted price = 0.75 * (11.88/0.92) * 0.92

the 0.92 cancel out

0.75 * 11.88 = 8.91

Ans A

gmatophobia · Answer

Let's assume that the cost of Quon's meal was $x

\frac{108x}{100} = 11.88

x = \frac{1188}{108}

Discount = 25%

Therefore cost of meal after discount =  \frac{3}{4} * \frac{1188}{108}

Discounted Bill + 8% tax =  \frac{3}{4} * \frac{1188}{108} * \frac{108}{100} = 8.91

Option A

Jyotimishra · Answer

hey,
why did we take 108/100 for 8% tax? shouldn't it be just 8/100?

gmatophobia · Answer

hello,

The information provided in the question premise mentions that $11.88 was the amount of the meal including tax. It's not just the tax component.

Let's assume that the cost of the meal = $ x

Tax =  \frac{8}{100} * x = 0.08x

Total Amount = Cost of the meal + Tax =  x + 0.08x = 1.08x = \frac{108x}{100}

Let me know if this doesn't help.

Jyotimishra · Answer

Hey, 
in the first part of the question where we have to calculate x I understood 108/100 but in the second half where u wrote “ Discounted Bill + 8% tax =” we already did the discounted bill calculation (3/4*x) then why did we multiply again with 108/100 instead of just 8/100 for 8% tax?

gmatophobia · Answer

The  25 % discount was applied to the meal (base price of the meal). Hence, we have used the factor  \frac{3}{4}  along with the price of the meal (denoted by x). However, the question asks us to find the value of the final bill. Quon's final bill was the discounted cost of the meal plus the 8% tax on the discounted cost of the meal.

Discounted cost of the meal =  \frac{3}{4} * \frac{1188}{108}

The value of the final bill can be computed as follows -

Final Bill =  Discounted cost of the meal  +  8% tax on the discounted cost of the meal.

=  \frac{3}{4} * \frac{1188}{108}   +   \frac{8}{100}*\frac{3}{4} * \frac{1188}{108}

=  \frac{3}{4} * \frac{1188}{108}*(1 + \frac{8}{100})

=  \frac{3}{4} * \frac{1188}{108} * \frac{108}{100}

nisen20 · Answer

just discount the total bill that includes certain amount of tax, since when doing so the extra tax Quon would have paid will be deducted simultaneously.
the tax rate in this question is a distraction, as we can see the order of operations doesn't matter.

(\frac{11.88}{1.08 } × \frac{3}{4}) × 1.08 = (\frac{11.88}{1.08 } × 1.08) × \frac{3}{4}

ruis · Answer

In case it helps someone when simplifying
1188 = 108*11
108 = 2^2 * 3^3

108*11/108 = 11
Now: 11*3/4*108/100;
11*3*3^3/100;
11*3^4/100;
11*81/100;
891/100 = 8,91

KarishmaB · Answer

Responding to a pm:

We DO NOT NEED to calculate the pre-tax bill amount and then take 25% off that. 
Say the pre-tax bill amount was x. Given:

x + .08x = 11.88

What I need to find is the bill amount once a 25% discount is taken and then the 8% tax on this new bill amount. This is what I need:

0.75x + .08*(0.75x) 
= 0.75 * (x + .08x)

This (x + .08x) is just the current total bill amount of $11.88. So all we have to do is find 3/4th of the $11.88 (discount of 25%)

\frac{3}{4} * $11.88 = $8.91

In simple words, a 25% discount on the pre-tax bill will automatically lead to a 25% discount on the tax (basics of percentages) and hence all we need to do is take a 25% discount on the given amount of $11.88.

Answer (A)

Percentages are discussed here:  https://youtu.be/HxnsYI1Rws8

hemanthPA · Answer

Given:
11.88 = X + 8X/100
X = 11

Discount coupon – 0.25 x 11 = 11/4
New price of the meal = 11 – 11/4 = 33/4

Final Bill
= 33/4 + (8*33/4)/100

= 8.25 + 0.66

= $8.91

alphab · Answer

11.88/0.92 should be 11.88/1.08 -- it works fine here because it cancels out but otherwise you are technically adding the factor representing the tax rate (or 1 minus the tax rate, since tax was 8%).

sujoykrdatta · Answer

If the original bill was $b, Quon had 25% discount on that followed by an increase of 8% due to tax
Thus, effectively, the original bill would be multiplied with 0.75 (25% decrease) and then again with 1.08 (8% tax)
Thus, final bill would be $(0.75 * 1.08 * b)

In the question, the value of the bill along with the 8% tax i.e. 1.08b is given equal to 11.88

Thus, we have: Final bill = 0.75 * 1.08b = 0.75 * 11.88 = $8.91
 Ans A

triptiim · Answer

It will be 1+8/100 = 108/100

Originally, the bill for Quon's meal wass $11.88, which included an 8%

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Originally, the bill for Quon's meal wass $11.88, which included an 8%

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards