another word problem

[lost46]

A cereal manufacturer has 2500 lb of a cereal mixture containing 25% corn, 40% sugar, 25% out flour, and 10% combination of wheat-starch and salt. If he wants to increase the percentage of corn content in the cereal mixture to 40%, how many pounds of corn should he add? (The answer in the book I have states 625lb. and the answer I come up with is 375lb.) I am working off of the word increase and assume it means the difference between 25% and 40%.

 

[Deleted member 4993]

A cereal manufacturer has 2500 lb of a cereal mixture containing 25% corn, 40% sugar, 25% out flour, and 10% combination of wheat-starch and salt. If he wants to increase the percentage of corn content in the cereal mixture to 40%, how many pounds of corn should he add? (The answer in the book I have states 625lb. and the answer I come up with is 375lb.) I am working off of the word increase and assume it means the difference between 25% and 40%.

First thing to do is to define variables (figure out what do you need to find and then name things)

how many pounds of corn should he add

amount of corn added = c pounds

He starts with how much corn = 2500 * 0.25 = 625 lbs

Amount of corn in the mixture after adding extra corn = 625 + c

If adds c pounds of corn into his mixture - what will be the weight of the mixture = 2500 + c

Now according to the problem - we need

0.40 = (625 + c)/(2500 + c)

Now solve for 'c' from the equation above.