Question

Ed

A running track has two straight sides with length 130 m and two semicircle
ends with radius 40 m. It takes Kat 20 seconds to jog 80 m. How long would
it take her to jog around the track 42 times? Give your answer in hours and
minutes, to the nearest minute.
40 m
130 m

Answer 1

1 hour 29 minutes and 29 seconds

Explanation:

We need to find the circumference of the two semicircles of the track (which forms a full circle of radius 40m):

pi×40×2 = 80pi

The total length of the track to be travelled would be:

(80pi+130+130) × 42 = (80pi+260) ×42

= 21 476m (Rounded to 5 s.f.)

80m/20s

1s = 80÷20

= 4m

For every 1 second, Kat travels 4m.

Total Time taken:

21 476÷4 = 5369 seconds

= 1 hour 29 minutes and 29 seconds