Carcass wrote:
The average of a set of five values is 12. If one number is deleted, the average of the set is decreased by 0.6. What is the value of the deleted number?
(A) 14.2
(B) 14.4
(C) 16.2
(D) 19.6
(E) 20.2
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GRE Tips and Tricks - UPDATED 11/20/2021Let a, b, c, d and e be the 5 numbers
The average of a set of five values is 12.We can write: \(\frac{a+b+c+d+e}{5} = 12\)
Multiply both sides by 5 to get:
\(a+b+c+d+e=60\)If one number is deleted, the average of the set is decreased by 0.6In other words, if e is deleted, the average of the 4 remaining numbers is 11.4
We can write: \(\frac{a+b+c+d}{4} = 11.4\)
Multiply both sides by 4 to get:
\(a+b+c+d=45.6\)What is the value of the deleted number?We have:
\(a+b+c+d+e=60\)\(a+b+c+d=45.6\)Subtract the bottom equation from the top equation to get: \(e = 14.4\)
Answer: B