SOLUTION: I am trying to help my daugther to solve this problem but I can't write an equation for this problem. "It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it, and

Algebra ->  Rate-of-work-word-problems -> SOLUTION: I am trying to help my daugther to solve this problem but I can't write an equation for this problem. "It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it, and      Log On


   

Question 207920: I am trying to help my daugther to solve this problem but I can't write an equation for this problem.
"It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it, and 7 minutes to prepare a chicken sandwich with extra 1 min. to serve it. How many sandwiches can be prepared spending 42 minute in preparation and 15 minutes on serving?"
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
"It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it,
and 7 minutes to prepare a chicken sandwich with extra 1 min. to serve it.
How many sandwiches can be prepared spending 42 minute in preparation and 15 minutes on serving?"
:
Let h = no. of hamburgers
Let c = no. of chicken sand
;
Prepare equation:
5h + 7c = 42
:
Serve equation
2h + 1c = 15
Arrange for substitution
1c = 15 - 2h
c = (15-2h)
:
Substitute (15-2h) for c in the 1st equation
5h + 7(15-2h) = 42
5h + 105 - 14h = 42
5h - 14h = 42 - 105
-9h = -63
h = %28-63%29%2F%28-9%29
h = +7 hamburgers
and
15 - 2(7) = 1 chicken sandwich
:
:
Check solutions in the serve equation
2(7) + 1(1) = 15 min