UPSC Prelims 2001 · General Studies
Question 141: Basic Numeracy
A conveyer belt delivers baggage at the rate of 3 tons in 5 minutes, and a second conveyer belt delivers baggage at the rate of 1 ton in 2 minutes. How much time will it take to get 33 tons of baggage delivered using both the conveyer belts?
AnswerThe answer is (b).
The first belt delivers 3 tons in 5 minutes, i.e. 0.6 ton a minute. The second delivers 1 ton in 2 minutes, i.e. 0.5 ton a minute. Together they deliver 1.1 tons a minute, so 33 tons take 33 / 1.1 = 30 minutes. Remember to add rates, not times, when machines work together.
Why each option is right or wrong
- (a) 25.5 minutes would deliver only 28 tons.
- (b) Right: 30 minutes.
- (c) 35 minutes would deliver 38.5 tons.
- (d) 40.75 minutes would deliver about 45 tons.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2001, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.