Bus A takes 21 minutes to complete its route. bus B take's 35 minutes to complete its route. if both buses leave the station at 7:30

a. M At what time will they arrive at the station at the same time?

To answer this question I tried to find a common multiple of 21 and 35 which I found to be 105. As they are in minutes 105 is 1 hour and 45 minutes; after this I found 1 hour 45 munutes after 7:30, I then got 9:15

9:15 is my answer