UPSC Prelims 2026 CSAT, question 50

Topic: Arithmetic

Q50

$X$ travels 6 km on a bicycle with average speeds of 5 km per hour, 10 km per hour and 4 km per hour during the first 1 km, the next 2 km and the remaining 3 km, respectively. $Y$ travels the same distances with average speeds of 4 km per hour, 10 km per hour and 5 km per hour, respectively. How many minutes early will $Y$ complete the journey if both $X$ and $Y$ start at the same time?

(a) 3
(b) 4
(c) 5
(d) 6Correct answer

Solution.

Answer: (d) 6

The total time taken by $X$ is $\frac{1}{5} + \frac{2}{10} + \frac{3}{4} = 0.20 + 0.20 + 0.75 = 1.15$ hours $= 69$ minutes.
The total time taken by $Y$ is $\frac{1}{4} + \frac{2}{10} + \frac{3}{5} = 0.25 + 0.20 + 0.60 = 1.05$ hours $= 63$ minutes.
Therefore, $Y$ completes the journey $69 - 63 = 6$ minutes early.