Problema Solution
Whitney Baer and Kim Davison are in a bicycle race, following a circular track. If they start at the same place and travel in the same direction, and Whitney completes a revolution every 40 seconds and Kim completes a revolution every 45 seconds, how long will it take them before they reach the starting point again simultaneously
Answer provided by our tutors
lets assume that Whitney will make w revolutions and Davison will make d revolutions then
w*40 = d*45 divide both sides by 5
8w = 9d
where w and d are integer
since (8,9) = 1 the smallest integer values for w and d are: w = 9 and d = 8
8*9 = 9*8 = 72 circles
or 9*40 = 8*45 = 360 s = 6 min
they will reach the starting point simultaneously after 6 minutes.