In a mixture of​ concrete, there are four

Question

lb of cement mix for each pound of gravel. If the mixture contains a total of 215

lb of these two​ ingredients, how many pounds of gravel are​ there?

Answer 1

Well, because there are 4 lb of cement for 1 lb of gravel, the ratio would be 4:1 for cement and gravel, respectively. Each of the items added together would be 5 pounds, but 1 of each 5 pounds is gravel, so 1/5 of the mixture is gravel. 1/5 * 215 = 43