Question

A thief after committing a theft, runs at a uniform speed of 50m/min. After 2 minutes, a policeman runs to catch him. He goes 60 m in 1st min and increases his speed by 5m/min every succeding min. After how many minutes, the policeman will catch the thief?

Answer 1

please find the attachment

Answer 2

Answer:

5 minutes

Step-by-step explanation:

Speed of the theif is 50 m/min

In 2 mins, the theif covers 100 m.

After 2 mins, the policeman runs to catch him, so in the third minute the policeman covers 60 m.

In the third minute the thief would cover 150 m.

 

Now policeman increases his speed by 5 m/ min (Student be careful units for speed is 5 m/min NOT just metres)

So, in the fourth minute:

Distance covered by policeman = 60 + 65 = 125 m

Distance covered by thief = 200 m

 

In the fifth minute:

Distance covered by policeman = 125 + 70 = 195 m

Distance covered by thief = 250 m

 

In the sixth minute:

Distance covered by policeman = 195 + 75 = 270 m

Distance covered by thief = 300 m

 

In the 7th  minute:

Distance covered by policeman = 270 + 80 = 350

Distance covered by thief = 350 m

Hence, after 7 minutes the policeman will catch the thief.

But 7th minute of thief is 5th minute of policeman