SOLUTION: A farmer can plant 8 trees in 6 days. His friend can plant 6 trees in 9 days. Working together, how many trees can they plant in 15 days?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A farmer can plant 8 trees in 6 days. His friend can plant 6 trees in 9 days. Working together, how many trees can they plant in 15 days?      Log On


   

Question 979975: A farmer can plant 8 trees in 6 days. His friend can plant 6 trees in 9 days. Working together,
how many trees can they plant in 15 days?
Found 2 solutions by solver91311, josgarithmetic:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


8 trees in 6 days is 4/3 trees in 1 day. 6 trees in 9 days is 2/3 of a tree in 1 day. Working together they plant 4/3 plus 2/3 trees or 2 trees per day. You can figure out the rest.

John

My calculator said it, I believe it, that settles it

Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
RT=J uniform rate model relating RATE, TIME, Amount of JOB.

The two farmers are farmer A at rate A and farmer B at rate B.
The rate model form can also be shown as R=J%2FT, and we can then use
this to assign A=8%2F6=4%2F3 and B=6%2F9=2%2F3, both in units of TREES per DAY.

Their combined rate if working together on the same work is A%2BB.

Question, how many trees j can A and B plant in t=15 days? The unknown variable is j.
%28A%2BB%29%2At=j

highlight_green%28j=%284%2F3%2B2%2F3%29%2A15%29
and you can do the arithmetic computation.