Question 309263
This is Least Common Multiple (LCM) problem.
First find out in how hours they will pass the first time. This number will be the LCM of 1.5 and 2.5
You can write out the multiples of these two numbers as follows:
1.5: 1.5, 3.0, 4.5. 6.0, 7.5, 9.0 ...
2.5: 2.5, 5.0, 7.5, 10.0...
You can see that the LCM is 7.5 which means that they will pass each other every 7.5 hours.
To see how many times they will do this in a 24-hour period, divide 24 by 7.5.
{{{24/7.5 = 3.2}}}
So the answer would be they would pass each other 3 times in a 24-hour period.