Question

The Stauffers take a trip from Seattle to San Francisco and back. Their trip takes 8 days. The Arnolds leave at the same time to make the same trip but it takes them 10 days. If the Stauffers and the Arnolds continue to make the trips, how many days will it be before they are both leaving Seattle at the same time?

Answer 1

* The Stauffers make the round trip in 8 days

* The Arnolds make the same round trip in 10 days

* This means the Stauffers complete 1.25 round trips for every 1 round trip the Arnolds make

* For them to leave Seattle at the same time again, the number of trips must be in a 1.25:1 ratio

* The lowest common multiple of 8 and 10 is 40

* So in 40 days, the Stauffers will have made 40/8 = 5 round trips

* And the Arnolds will have made 40/10 = 4 round trips

* Therefore, it will take 40 days for them to leave Seattle at the same time again.

The answer is 40 days.