Ryan, Howard and Fabian started walking at the same time from the same starting point round a circular track. Fabian walked in the clockwise direction. Ryan and Howard walked in an anti-clockwise direction. Fabian took 12 min to complete each round. He met Ryan after every 2 minutes. He met Howard after every 6 minutes. The three friends kept to their respective speeds throughout their walk.

1. How many rounds did Fabian complete in 1 h?
2. When Fabian and Ryan met again at the starting point after 1 h, Howard had completed 2.7 km. Find the circumference of the circular track in metres.

(a)
1 h = 60 min

Number of rounds that Fabian completed in 1 h
= 60 ÷ 12
= 5

(b)
Fabian took 12 min to complete 1 round
1 min = ¹₁₂ of circular track = 1 u
12 min = ¹²₁₂ of circular track = 12 u

Fabian's distance is the repeated identity.
Make Fabian's distance the same.

Fabian's distance : Ryan's distance
2 : 12 - 2
2 : 10

Fabian's distance : Howard's distance
6 : 12 - 6
6 : 6

Fabian	Ryan	Howard
2x3	10x3
6x1		6x1
6	30	6

The distance of Fabian is the repeated identity. 
LCM of 2 and 6 = 6

In 1 h
Fabian's rounds : Ryan's rounds : Howard's rounds
6 : 30 : 6

Distance that Howard completed in 1 h = 2.7 km

6 rounds = 2.7 km = 2700 m

1 round = 2700 ÷ 6 = 450 m

Circumference of the circular track = 450 m

Answer(s): (a) 5; (b) 450 m