Question

There were three parts to Rita's race. she ran the first part, which was 4/9 of the total distance, in 20 minutes. She ran the second part, which was 2/5 of the remaining distance, in 12 minutes. She finally ran the third part in 15 minutes at a speed of 300 meters per minute.

a) How long was the third part of the race?

Answer 1

20+12+15= 32+15 = 47 minutes in total

300 meters per minute

300 * 47 = 14100 meters in total

with this we can see the first race was 4/9 that distance meaning the first race was 6266.6 meters long

14100 - 6266.6 = 7833.3

2/5 of 7833.3 is 3133.32

therefore 7833.3 - 3133.32 will give the distance of the third part of the race

meaning of course the answer is 4699.98 or rounding up 4700 meters for the third race