Question

tony completes one lap of a track every 20 seconds. diana completes one lap of the same track every 55 seconds. suppose tony and diana start at the starting line at the same time. how many seconds will it be before they cross the starting line at the same time again?This is a fraction word problem

Answer 1

Given:

The time taken for Tony to complete one lap is 20 s.

The time taken for Diana to complete one lap is 55 s.

The cumulative lap timing of Tony and Diana can be calculated as,

$\begin{gathered} \text{Tony}\rightarrow20,40,60,80,100,120,140,160,180,200,220\ldots. \\ \text{Diana}\rightarrow55,110,165,220,\ldots\text{.} \end{gathered}$

Since we can see that the common time is 220 s, they will cross at 220 s again.

This, is also same as that of the LCM of 20 and 55 which is also equal to 220.