Question

A thief runs with a uniform speed of 100 m/min. After one minute a policeman runs after the thief to catch him. He goes with a speed of 100 m/min in first minute and increases his speed by 10 m/min every succeeding minute. After how many minutes the policeman will catch the thief.

Answer 1

distance travelled by thief = `100m/min xx 1 min`
`= 100m`
distance between thief andd police men `= 100m`
after 2 mins
3 mins ; `d = 100-10 = 90metre`
`120-> 100 , 4 min`
`d = 70-20 = 70 m`
`130-> 100 ; 5min`
`d = 70-30 = 40 m`
`140 -> 100; 6min`
`d-> 40-40 = 0m`
so, `40m`
after 6 mins policeman will catch the thief
`= 10+20+30+40----= 100metre`
6 min answer