100+ Ratio and Proportion Questions for SBI PO, SO, Clerk Exams - 1

Ans: B

Let the fourth proportional to 0.12, 0.21 and 8 be x.

Then, 0.12 : 0.21 : : 8 : x

⇔ x = 0.12x = 0.21 × 8

⇔ x = $${0.21 × 8}/{0.12}$$ = $${21 × 8}/ {12}$$ = 14.

Ans: B

Abhinav’s investment = Rs. 6000.

Sunil’s investment = (100 - 30)% of 6000

= 70% of Rs. 6000 = Rs. $$({70}/{100} × 6000)$$ = Rs. 4200.

Rita’s investment = (100 + 25)% of Rs. 4200 =

125% of Rs. 4200 = Rs. $$({125}/{100} × 4200)$$ = Rs. 5250.

Total amount invested = Rs. (6000 + 4200 + 5250) = Rs. 15450.

∴ Required ratio = 5250 : 15450 = 35 : 103.

Ans: C

Required mean proportional = $$√ 0.02 × 0.32$$ = $$√ 0.0064$$ = 0.08.

Ans: D

Let the man’s expenditure be Rs. 26x and savings be Rs. 3x.

Then, monthly income = Rs. (26x + 3x) = Rs. (29x).

So, 29x = 7250 or x = 250.

∴ Monthly savings = Rs. (3 × 250) = Rs. 750.

Ans: C

Number of boys = $$(720 × {7}/{12})$$ = 420.

Number of girls = (720 - 420) = 300.

Let the required number of girls be x. Then, $${420}/{300 + x}$$ = 1

⇒ 420 = 300 + x ⇒ x = 120.