Category: Basic Athematic MCQs

Correct Answer: A. 180

Let the five numbers be P, Q, R, S and T.

=> P + Q + R + S + T = 655.
(P + Q)/2 = 85 and R = 125
P + Q = 170 and R = 125
P + Q + R = 295
S + T = 655 – (P + Q + R) = 360
Average of the last two numbers = (S + T)/2 = 180

Correct Answer: B. 174

Average = (312 + 162 + 132 + 142 + 122)/5 = 870/5 = 174

Correct Answer: C. 12

The initial average age of the 10 persons is P.
Age of the new person Q.
Sum of the ages of the initial 10 persons = 10P
New average = (P-3) 10(P-3) = 10P – 42 + Q => Q = 12

Correct Answer: A. 72

Sum of the marks for the 12 students = 12 * 36 = 432. The marks of each student are doubled, the sum also will be doubled.
The new sum = 432 * 2 = 864. So, the new average = 864/12 = 72

Correct Answer: B. 27

Sum of the 10 numbers = 230
If each number is increased by 4, the total increase =
4 * 10 = 40
The new sum = 230 + 40 = 270 The new average = 270/10 = 27

Correct Answer: B. 125

Sum of the 35 numbers = 35 * 25 = 875
If each number is multiplied by 5, the sum also gets multiplied by 5 and the average also gets multiplied by 5.
Thus, the new average = 25 * 5 = 125

Correct Answer: D. 52.5

Sum of the marks for the class of 30 students = 30 * 40 = 1200
Sum of the marks for the class of 50 students = 50 * 60 = 3000
Sum of the marks for the class of 80 students =
1200 + 3000 = 4200
Average marks of all the students = 4200/80 = 52.5

Correct Answer: C. 19

Let the average after the 16th inning be P.
So, the average after the 15th inning will be (P-3) Hence, 15(P-30) + 64 = 16P => P = 19

Correct Answer: A. 46

Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 7 of them = 7 * 57 = 399
Sum of the last 7 of them = 7 * 61 = 427
So, the 8th number = 427 + 399 – 780 = 46

Correct Answer: D. 10.5

Average of the first ‘n’ natural numbers = (n + 1)/2
We get (20 + 1)/2 = 10.5