SOLUTION: The Cost C of manufacturing a certain product can be estimated by the formula C = 0.03rst^2, where r and s are the amounts in pounds, of the two major ingredients and t is the pr

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The Cost C of manufacturing a certain product can be estimated by the formula C = 0.03rst^2, where r and s are the amounts in pounds, of the two major ingredients and t is the pr      Log On


   

Question 338648: The Cost C of manufacturing a certain product can be estimated by the formula
C = 0.03rst^2, where r and s are the amounts in pounds, of the two major ingredients and t is the production time in hours. If r is increased by 50 percent, s is increased by 20 percent, and t is decreased by 30 percent, by approximately what percent will the estimated cost of manufacturing the product change?
(A) 40% increase
(B) 12% increase
(C) 4% increase
(D) 12% decrease
(E) 24% decrease
The answer is(D) 12% decrease but I am getting 26%. Could you please explain.

Thanks
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
See this previous solution. Let me know if you still need more help.