Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d = A. Cannot be determine

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d = A. Cannot be determine

by BTGmoderatorDC » Fri Sep 25, 2020 5:27 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d =

A. Cannot be determined
B. -5
C. -10
D. -15
E. -20


OA C

Source: Magoosh
Top
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Wed Jun 29, 2011 1:47 am

Re: If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d = A. Cannot be deter

by psarma » Sat Sep 26, 2020 11:41 am
Given \(\frac{b+c}{2}\) =5
So, b+c = 10

Likewise, \(\frac{c+d}{2}\) =10
So, c+d=20

Subtracting 2nd equation from 1st,
we get b-d=-10

Answer is C.
Top
Moderator
Posts: 2246
Joined: Sun Oct 29, 2017 2:08 pm
Followed by:2 members

Re: If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d = A. Cannot be deter

by AAPL » Sat Sep 26, 2020 11:47 am
BTGmoderatorDC wrote: ↑
Fri Sep 25, 2020 5:27 pm
 If the average (arithmetic mean) of b and c is 5, and the average of c and d is 10, then b - d =

A. Cannot be determined
B. -5
C. -10
D. -15
E. -20


OA C

Source: Magoosh
\begin{cases}
b + c = 10 \qquad (1) \\
c + d = 20 \qquad (2)
\end{cases}

Subtracting \((1)\) from \((2)\) we have,

\(b - d = -10\)
Top
Post new topic Post Reply
• Page 1 of 1