Question

A contractor mixes concrete from bags of pre-mix for small jobs.
How many bags with 3% cement should he mix with 10 bags of 6.2% cement to produce a mix containing 5% cement?

please help, very confused here

Answer 1

I think it's asking how many bags of 3% should they mix with 10 bags of 6.2% of cement to create a mix with only 5% of cement.

Answer 2

So like a+b= 5%
a= 3% bags of cement
b= 10 bags of 6.2% cement

Answer 3

yes but how would i go about starting the equation?

Answer 4

I'm not entirely sure, I'm sorry. I think you should get someone elses help. All I know is the formula, not how do it.

Answer 5

what is throwing me off is the 10 bags of 6.2% cement, how would you write that in the formula?
the process I could do if I could set up the formula correctly

Answer 6

I'm not sure. I think it's how to calculate 5% out of (10*6.2%) and 3%.

Answer 7

I will check if it works that way. Thanks! :)

Answer 8

Yup! Sorry I couldn't be the best of help!