GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 13 Nov 2018, 10:29

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
• ### Essential GMAT Time-Management Hacks

November 14, 2018

November 14, 2018

07:00 PM PST

08:00 PM PST

Join the webinar and learn time-management tactics that will guarantee you answer all questions, in all sections, on time. Save your spot today! Nov. 14th at 7 PM PST
• ### $450 Tuition Credit & Official CAT Packs FREE November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) # Two oil cans, X and Y, are right circular cylinders, and the height an  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags Math Expert Joined: 02 Sep 2009 Posts: 50570 Two oil cans, X and Y, are right circular cylinders, and the height an [#permalink] ### Show Tags 10 Dec 2017, 07:05 00:00 Difficulty: 25% (medium) Question Stats: 85% (01:30) correct 15% (01:20) wrong based on 42 sessions ### HideShow timer Statistics Two oil cans, X and Y, are right circular cylinders, and the height and the radius of Y are each twice those of X. If the oil in can X, which is filled to capacity, sells for$2, then at the same rate, how much does the oil in can Y sell for if Y is filled to only half its capacity?

(A) $1 (B)$ 2
(C) $3 (D)$ 4
(E) $8 _________________ Manager Joined: 22 Apr 2017 Posts: 110 Location: India GMAT 1: 620 Q46 V30 GMAT 2: 620 Q47 V29 GMAT 3: 630 Q49 V26 GMAT 4: 690 Q48 V35 GPA: 3.7 Two oil cans, X and Y, are right circular cylinders, and the height an [#permalink] ### Show Tags Updated on: 10 Dec 2017, 08:37 Bunuel wrote: Two oil cans, X and Y, are right circular cylinders, and the height and the radius of Y are each twice those of X. If the oil in can X, which is filled to capacity, sells for$2, then at the same rate, how much does the oil in can Y sell for if Y is filled to only half its capacity?

(A) $1 (B)$ 2
(C) $3 (D)$ 4
(E) $8 Let's suppose Cylinder X has a radius r and height h. Cylinder Y radius =2r, height 2h. X contains πr^2h ltrs of oil which sells for 2$.

Y is half filled...so volume of oil in Y....1/2(π(2r)^2 2h) = 4πr^2h
So oil in Y will sell for 4 rate of x===> 4x2$= 8$ Hence E

Originally posted by ManishKM1 on 10 Dec 2017, 08:08.
Last edited by ManishKM1 on 10 Dec 2017, 08:37, edited 1 time in total.
Intern
Joined: 25 Jul 2017
Posts: 39
Re: Two oil cans, X and Y, are right circular cylinders, and the height an  [#permalink]

### Show Tags

10 Dec 2017, 08:26
1
Hi all, IMO, answer should be E: $8. V of cylinder = R^2*H. If height and radius of Y double height and radius of X --> V(Y) = 8V(X) ---> Price for full capacity of Y = 8 price for full capacity of X = 8*$2=$16 --> Price for half capacity of Y =$16/2=$8 Please kudo if it helps. Thanks. Senior SC Moderator Joined: 22 May 2016 Posts: 2090 Two oil cans, X and Y, are right circular cylinders, and the height an [#permalink] ### Show Tags 10 Dec 2017, 14:38 1 Bunuel wrote: Two oil cans, X and Y, are right circular cylinders, and the height and the radius of Y are each twice those of X. If the oil in can X, which is filled to capacity, sells for$2, then at the same rate, how much does the oil in can Y sell for if Y is filled to only half its capacity?

(A) $1 (B)$ 2
(C) $3 (D)$ 4
(E) $8 Choose smart numbers Calculate the amount of oil in X and Y with the formula for the volume of a right circular cylinder. Y's oil volume times the sell rate for X's oil = selling price for Y's oil Volume of right circular cylinders: $$\pi r^2 h$$ For oil can X: Let $$r = 1$$ and $$h = 1$$ For oil can Y: Let $$r = 2$$ and $$h = 2$$ X is full. The amount of oil in X = X's volume X's oil amt: $$\pi r^2 h=\pi(1)(1)= 1\pi$$ Y is half full. Y's oil amount is half of Y's volume Y's volume: $$\pi r^2h =\pi (4)(2)=8\pi$$ Y's oil amount: $$\frac{8\pi}{2}= 4 \pi$$ X's oil sells for$2. Y has 4 times as much oil as X. Y's oil sells for ($2 * 4) =$8

OR $$\frac{2}{1 \pi}=\frac{y}{4 \pi}$$

$$y = 8$$

Algebraically
Volume of right circular cylinder: $$\pi r^2 h$$
Height of Y = 2 * height of X

Amount of oil in X = Volume of X = $$\pi r^2 h$$

Y's oil amount = half of Y's volume: $$(\frac{1}{2})*\pi (2r)^2(2h)=(\frac{1}{2})\pi(4r^2)(2h)=4\pi r^2h$$

X's oil sells for \$2. Y's oil sells for?
$$\frac{1(\pi r^2h)}{4(\pi r^2h)} = \frac{2}{y}$$

$$y = 8$$

Two oil cans, X and Y, are right circular cylinders, and the height an &nbs [#permalink] 10 Dec 2017, 14:38
Display posts from previous: Sort by