Question

In a mixture of concrete, there are five lb of cement mix for each pound of gravel. If the mixture contains a total of 258 lb of these two ingredients, how many pounds of gravel are these?

Answer 1

amount of gravel + the amount of cement = mixture

You are given that there is 5 pounds of cement to one pound of gravel. So the mixture contains an amount of cement that is 5 times the amount of gravel.

So if you let g = gravel then the amount of cement must be 5 times g.

So the equation will look like this:

g+5g=258