Sel run around a track 3 times in 8 minutes. Mar run around the same track 2 times in 5 minutes.If sel and Mar begin at the same time and same place, what is the combined number of laps they both would have run when they next reach starting point at same time?
Sel runs 3/8 lap in one minute
Mar runs 2/5 lap in one minute
So.... Mar runs (2/5 - 3/8) = [ 16 - 15] / 40 = 1/40 of a lap farther than Sel does in one minute
So....in 40 minutes....they will be even again
In this time Sel runs (3/8)*40 = 15 laps
And Mar runs (2/5)*40 = 16 laps
So...combined.....they run 15 + 16 = 31 laps
3L/8min 2L/5min find(lowest) common denominator (40)
15L/40min 16L/40min At 40 minutes they will have combined 15+16 = 31 laps
(added 'lowest')