SOLUTION: Hi,
I would like to say thank you in advance.
My question is:
A certain punch press requires 2 hours longer to stamp a box of parts than does a newer-model punch press. Af
Question 1011086: Hi,
I would like to say thank you in advance.
My question is:
A certain punch press requires 2 hours longer to stamp a box of parts than does a newer-model punch press. After the old press has been punching a box of parts for 5 hours, it is joined by the new machine. Together, they finish the box of parts in 3 additional hours. How long does it take each machine, working alone, to punch a box of parts.
Thank you Found 2 solutions by josgarithmetic, Boreal:Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
RATES
certain old
new model
both combined
One job is "stamp a box of parts".
----------Most important is that this make sense and you learn to formulate it yourself.
The rest is arithmetic. Tell if you need more help. Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website! new model takes x hours to do the whole thing. In 1 hour, it does 1/x
old model takes x+2 hours to do the whole thing. In 1 hour, it does 1/(x+2)
8/(x+2)+3/x=1
x(x+2)=8x+3(x+2), clearing fractions by multiplying everything by x(x+2)
x^2+2x=11x+6
x^2-9x-6=0
x=(1/2)(9+sqrt(81+24); sqrt 105=10.25
x=(1/2)19.25=9.63 hours, only positive root. That is new punch press. The old one takes 11.63 hours.
After 5 hours,
old punch pass has done 8/11.63=0.688 of the job
the new one does 3/9.63 = 0.311 of the job