Uncle Bruce is baking chocolate chip cookies. He has 36 ounces o

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

BTGModeratorVI: Legendary Member; Posts: 1223; Joined: Sat Feb 15, 2020 2:23 pm; Followed by:1 members

Uncle Bruce is baking chocolate chip cookies. He has 36 ounces o

by BTGModeratorVI » Tue Mar 31, 2020 5:13 am

Timer

00:00

Your Answer

Global Stats

Uncle Bruce is baking chocolate chip cookies. He has 36 ounces of dough (with no chocolate) and 15 ounces of chocolate. How much chocolate is left over if he uses all the dough but only wants the cookies to consist of 20% chocolate?

(A) 3
(B) 6
(C) 7.2
(D) 7.8
(E) 9

Answer: B
Source: Veritas Prep

Quote

Source: Beat The GMAT — Problem Solving | Tue Mar 31, 2020 5:13 am

swerve: Legendary Member; Posts: 2499; Joined: Sun Oct 29, 2017 2:04 pm; Followed by:6 members

Re: Uncle Bruce is baking chocolate chip cookies. He has 36 ounces o

by swerve » Tue Mar 31, 2020 10:00 am

BTGModeratorVI wrote: ↑
Tue Mar 31, 2020 5:13 am
Uncle Bruce is baking chocolate chip cookies. He has 36 ounces of dough (with no chocolate) and 15 ounces of chocolate. How much chocolate is left over if he uses all the dough but only wants the cookies to consist of 20% chocolate?

(A) 3
(B) 6
(C) 7.2
(D) 7.8
(E) 9

Answer: B
Source: Veritas Prep

Let the total weight of cookies \(= x\)

dough used \(= 36\) ounces, which is \(80\%\) of the total

\(\Longrightarrow \dfrac{80}{100}\cdot x =36 \Longrightarrow x= 45\) ounces

Out of \(45\) ounces, \(20\%\) is chocolate \(\Longrightarrow \dfrac{20}{100}\cdot 45 = 9\) ounces

Thus, leftover chocolate \(= 15 - 9 = 6\) ounces.

Hence, the correct answer is B

Quote

GMAT/MBA Expert

Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pm; Location: Vancouver, BC; Thanked: 5254 times; Followed by:1268 members; GMAT Score:770

Re: Uncle Bruce is baking chocolate chip cookies. He has 36 ounces o

by Brent@GMATPrepNow » Tue Mar 31, 2020 1:41 pm

BTGModeratorVI wrote: ↑
Tue Mar 31, 2020 5:13 am
Uncle Bruce is baking chocolate chip cookies. He has 36 ounces of dough (with no chocolate) and 15 ounces of chocolate. How much chocolate is left over if he uses all the dough but only wants the cookies to consist of 20% chocolate?

(A) 3
(B) 6
(C) 7.2
(D) 7.8
(E) 9

Answer: B
Source: Veritas Prep

We can use equivalent ratios.

The cookies will consist of 20% chocolate.
In other words, the cookies will consist of 1/5 chocolate.
We can also say the cookies will consist of 4/5 dough.

This means the cookies are 4 parts dough and 1 part chocolate.
So, the dough to chocolate ratio = 4/1

We have 36 ounces of dough available.
Let c = the number of ounces of chocolate needed.

We now can use equivalent ratios to set up the equation: 4/1 = 36/c
Solve to get c = 9

So, we need to USE 9 ounces of chocolate, which leaves us with 6 ounces REMAINING.

Answer: B

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

Quote

GMAT/MBA Expert

Scott@TargetTestPrep: GMAT Instructor; Posts: 8086; Joined: Sat Apr 25, 2015 10:56 am; Location: Los Angeles, CA; Thanked: 43 times; Followed by:29 members

Re: Uncle Bruce is baking chocolate chip cookies. He has 36 ounces o

by Scott@TargetTestPrep » Wed Apr 01, 2020 4:14 pm

BTGModeratorVI wrote: ↑
Tue Mar 31, 2020 5:13 am
Uncle Bruce is baking chocolate chip cookies. He has 36 ounces of dough (with no chocolate) and 15 ounces of chocolate. How much chocolate is left over if he uses all the dough but only wants the cookies to consist of 20% chocolate?

(A) 3
(B) 6
(C) 7.2
(D) 7.8
(E) 9

Answer: B
Source: Veritas Prep

Let x = the amount of chocolate to be used so that the cookies consist of 20% chocolate. We have:

x/(36 + x) = 20/100

x/(36 + x) = 1/5

5x = 36 + x

4x = 36

x = 9

Thus, if the cookies are to contain 20% chocolate, 15 - 9 = 6 ounces of chocolate will remain.

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]