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Working together, Melissa and Jing can mow a lawn in 5 hours. It would take Melissa 8 hours to do the job alone.What is the value of r, the part of the lawn that Jing could complete in 1 hour?

Respuesta :

apologiabiology
so
work=rate tmes time
we have
Jrate
Jtime
Jwork
Mrate
Mtime
Mwork

so if Mtime and Jtime=5, Jwork+Mwork=1 lawn
if Mtime=8, then Mwork=1
Mtime=8
Mwork=1
Mrate=?
Mtime times Mrate=Mwork
8 times ?=1
diivde both sides by 8
?=1/8
Mrate=1/8 lawn per 1 hour

so find Mwork for 5 hours
Mwork=Mrate times Mtime
Mtime=5
Mrate=1/8
Mwork=5 times 1/8
Mwork=5/8

Mwork+Jwork=1=8/8
5/8+Jwork=8/8
subtract 5/8
Jwork=3/8

Jwork=3/8
Jtime=5
Jrate=?
Jwork =Jtime times Jrate
3/8=5 times Jrate
divide both sides by 5 or mutliply both sides by 1/5
3/40=Jrate




answer is 3/40 lawn in 1 hour for Jing