# Math Help - anybody help this problem

1. ## anybody help this problem

The average of a, b and c is 56. The average of b, c and d is 42. What is the value of (a d)?

(A) 98

(B) 42

(c) 36

(D) 28

( E ) 14

2. Originally Posted by sri340
The average of a, b and c is 56. The average of b, c and d is 42. What is the value of (a d)?

(A) 98

(B) 42

(c) 36

(D) 28

( E ) 14
$\frac{a + b + c}{3} = 56 \implies a + b + c = 168$

$\frac{b + c + d}{3} = 42 \implies b + c + d = 126$

I can get you a - d. Is that what you needed?
$(a + b + c) - (b + c + d) = 168 - 126$

$a - d = 42$

-Dan