A man starts to run along a particular direction with a speed of 54 km./hours. After running upto a

M4maths Previous Puzzles

10 Jun 2011 run

A man starts to run along a particular direction with a speed of 54 km./hours. After running upto a distance of 100 m, he increases his speed by 50 % of the initial speed, and runs upto 200 m. Total time taken by the man will be

OPtion

1) 10
2) 11.5
3) 12.5
4) 15.5
5) 16
6) 18.5
7) 20.5
8) 21
9) 22.5
10) None of these

Solution

54 km./hour = 54*5/18 = 15 m/s
81 km./hour = 81*5/18 = 22.5 m/s
so total time = (100/15)+(200/22.5) = 15.5 sec.

Correct Option: 4 Best Solution (0)