Question

Ty and Marshon are brothers.  Their grandmother wants her leaves raked and the yard mowed.  When Ty does the work on his own he can complete the work in 6 hours.  It takes Marshon 10 hours to complete the work on his own.  Today, their grandmother wants her grandsons to work together to complete the work.  How many hours will it take Ty and Marshon to rake the leaves and mow the lawn when they work together? (Do not round your answer.)

Answer 1

I am not 100% sure so please don't hate me if I am wrong.

6 + 10= 16
Divide by 2 becuase they are working together.
It takes them 8 hours to get the work done together.

Answer 2

There is a formula for that
(worker1 * worker2) / (worker1 + worker2)

(6 * 10) / (6 + 10) =
60 / 16 =
15/4 = 3.75 hours

Without using a formula, Ty can do 1/6 of the work in 1 hour.
Marshoc can do 1/10 of the work in 1 hour.
Working together they can do
1/6 + 1/10 = 10/60 + 6/60 =

16/60 of the work in one hour
or the total job will get done in
1 / (16/60) = 3.75 hours