averages Model Questions & Answers, Practice Test for ibps rrb po prelims

Answer: (d)

R - Q = R - T ⇒ Q = T.

Also, R + T = 50

⇒ R + Q = 50

So, (R - Q) cannot be determined.

Answer: (d)

Let the present ages of the father and son be 2x and x years respectively.

Then, (2x - 18) = 3 (x - 18) ⇔ x = 36.

∴ Required sum = (2x + x) = 3x = 108 years.

Answer: (c)

Let the total no. of workers be x.

Now, 8000 x = 7 × 12000 + (x - 7) × 6000

⇒ $x = 42000/2000 = 21$

Answer: (b)

Let their age be A, B and C respectively.

⇒ ${A + B + C}/3 = 24$

⇒ A + B + C = 72 --- (i)

⇒ ${A - 4 + B - 4}/2 = 18$

⇒ ${A + B - 8}/2 = 18$

A + B = 44 --- (ii)

eq(i) - eq (ii)

(A + B + C) - (A + B) = 72 - 44

C = 28 years

After 8 years age of C

= 28 + 8 = 36 years

So, option (c) is correct.

Answer: (d)

Let C's age be x years.

Then, B's age = 2x years.

A's age = (2x + 2) years.

∴ (2x + 2) = 2x + x = 27

⇔ 5x = 25 ⇔ x = 5.

Hence, B's age = 2x = 10 years.