Question

Stephanie can catch one of the two scheduled trains to go home from a station.
Train 1 arrives at the station every 24 minutes, and train 2 arrives every 36 minutes. If both the trains are at the station right now, then after how many minutes will they both arrive again?

• A. 1 h 12 min
• B. 46 min
• C. 1 h 32 min
• D. 58 min

Answer 1

The correct option is A 1 h 12 min

To solve this problem, we need to find the least common multiple of the two given numbers.

Let's find the LCM using the ladder method.


$\text{LCM (24, 36):}2\times 2\times 2\times 3\times 3=72$

$\text{60 min = 1 h}$
$\text{72 min = 1 h + 12 min}$

Hence, both trains would arrive again at the station after 1 hour 12 minutes.