2014 CSAT, all questions
UPSC Prelims 2014 · CSAT
Question 69: Basic Numeracy
Two cars start towards each other, from two places A and B which are at a distance of 160 km. They start at the same time 08 : 10 AM. If the speeds of the cars are 50 km and 30 km per hour respectively, they will meet each other at
a10 : 10 AM
b10 : 30 AM
c11 : 10 AM
d11 : 20 AM
AnswerUPSC’s answer is (a).
The cars approach each other, so their speeds add: 50 + 30 = 80 km/h. Time to close the 160 km gap = 160 / 80 = 2 hours. Starting at 8:10 AM they meet at 10:10 AM. For two bodies moving towards each other, use a relative speed equal to the sum of the speeds.
Why each option is right or wrong
- (a) Right. Two hours after 8:10 is 10:10.
- (b) 10:30 would be 2 hours 20 minutes, which is too long at 80 km/h.
- (c) 11:10 would need 3 hours.
- (d) 11:20 would need 3 hours 10 minutes.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2014, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.