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

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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 $\displaystyle \frac{a + b + c}{3} = 56 \implies a + b + c = 168$ $\displaystyle \frac{b + c + d}{3} = 42 \implies b + c + d = 126$ I can get you a - d. Is that what you needed? $\displaystyle (a + b + c) - (b + c + d) = 168 - 126$ $\displaystyle a - d = 42$ -Dan

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