Question 750288
A student must leave for campus in 10 minutes or he will be late for class.
 Unfortunately, he is snowed in.
 He can shovel the driveway in 16 minutes, and his brother claims to be able to do it in 14 minutes.
 If they shovel together, how long will it take to clear the driveway?
 Will this give enough time for the student to get to the campus?
:
Use a shared work equation, let t = time working together
Let the completed job = 1 (a cleared driveway)
:
{{{t/16}}} + {{{t/14}}} = 1
multiply equation by the least common multiple of 16 and 14, that 112, results:
7t + 8t = 112
15t = 112
t = 112/15
t = 7.47 minutes, so you are right!