Question

The mean of five numbers is 80, out of which mean of 4 numbers is 46, find the 5th number. Write the correct alternative answer for the question.
(A) 4
(B) 20
(C) 434
(D) 66

Answer 1

According to first condition,

a1 +a2 + a3 + a4 + a5 / 5 = 80

=> a1 +a2 + a3 + a4 + a5 = 400 ------(1)

According to second condition,

a1 +a2 + a3 + a4 /4 = 46

=> a1 +a2 + a3 + a4 = 184 -----(2)

On subtracting equation 1 from 2, we get

a5 = 400 - 176

=> a5 = 216

Answer 2

Given ,
Mean of 5 numbers = 80 .

Now ,
Sum of 5 numbers = 80 * 5 = 400 .

Also ,
Mean of 4 numbers = 46

Sum of 4 numbers = 46 * 4 = 184 .

Now ,

Fifth number = Sum of 5 numbers - Sum of four numbers = 400 - 184 = 216 .

The fifth number is 216 .

In the given option , it doesnt exist . so Correct option is none of these