for the second one, because there are 60 minutes in a hour, multiply 12 by 5 and u get 60, then multiply 7/8 by 5/1 and u get the answer.
for the third multiply 8 and 5 and u get 40. Then multiply 1/2 by 5/1 and u will get the answer.
Sorry for the first one though
hope this helped!