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
Moderator
Posts: 6595
Joined: 07 Sep 2017
Followed by:20 members

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

Junior | Next Rank: 30 Posts
Posts: 24
Joined: 29 Jun 2011
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.

Moderator
Posts: 2064
Joined: 29 Oct 2017
Followed by:2 members
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,

\(b - d = -10\)