Let time Mark takes to mow by himself, be M

Then Mark can mow 1/M of lawn in 1 hour

Lisa can mow lawn in 3 hours, or 1/3 of lawn in 1 hour

Therefore, 



3 + M = 3M ------ Multiplying by LCD, 3M

3 = 3M - M

2M = 3

M, or time Mark takes, alone, to mow = , or  hours

Mark's rate: , or , or  of lawn in 1 hour 

RELATED QUESTIONS

If lisa can mow a lawn by herself in 3 hours what is her... (answered by Edwin McCravy)

Together, Diane and Craig can mow their lawN in 1 hour and 10 minutes. Working alone,... (answered by josgarithmetic,josh_jordan)

Fred can mow the lawn in 1 hour. John can mow the lawn in 2 hours. How long will it take... (answered by stanbon)

If bob can mow a lawn in 5 hours, and jim can mow the same lawn in 3 hours,how long will... (answered by mananth)

Can you help me with this problem? Jill and Sarah are mowing a lawn together (with... (answered by stanbon)

Bob can mow the lawn in 5 hours, and Fred can mow the lawn in 4 hours. How long will it... (answered by josgarithmetic)

John can mow a lawn in 2 hours, and Peter can mow the same lawn in 3 hours. How long... (answered by amarjeeth123)

Stephen and Kyle are brothers. Stephen can mow the lawn in 1 hour. Kyle takes 2 hours to... (answered by richwmiller)

Terri and Judy run a lawn mowing business.  If Terri can mow a large lawn in 8 hours and... (answered by Alan3354)