Question 157157

Let x=amount of time it takes them both working together to mow the yard
Jack mows at the rate of 1/6 yard per hour
Marilyn mows at the rate of 1/7 yard per hour
Together they mow at the rate of 1/6 +1/7 or 7/42 + 6/42=13/42 yard per hour
So, our equation to solve is:
(13/42)*x=1 (1 yard, that is) multiply each side by 42
13x=42 divide each side by 13
x=42/13 or 3 3/13 hour 

CK
(1/6)(42/13)=7/13
(1/7)(42/13)=6/13
7/13 + 6/13=13/13 or 1 yard

Hope this helps---ptaylor