The answer is 102. Simply add the numbers together arithmetically as you would for the problem two plus two. To check your work, a calculator is the best option.
There are 60 minutes in each hour. That 402 minutes (6 x 60 plus 42)
60-42 = 18
42 / .60 = 70
The GCF of 42, 60, 78 is 6.
42 minutes/1 hour = 42 minutes/60 minutes = 42/60 = 7/10
18 + 42 = 60
60
42
60
42
There are 60 minutes in each hour. That 402 minutes (6 x 60 plus 42)
7/12 + 7/10 = 35/60 + 42/60 = 77/60 or 117/60
60-42 = 18
360
42 subtracted by 60 = -18
100*42/60 = 70%
42 is 60% of 70