Expressions

Question

 A group of cows produced the same number of gallons of milk each day for a week. Sarah collected the milk for six days. Write an expression to show the number of gallons Sarah did not collect. 

Answer 1

Michelle from sunny Sacramento,

 

The cows produce the same number of gallons each day for a week. So, we have G gallons for the week (or 7 days). Our variable is G for the total number of gallons produced by the cows. She didn't collect 1 out of the 7 days. As a fraction, "1 out of 7" is (1/7). This means (1/7) of the total amount of milk she could have collected was not collected. So, the amount Sarah didn't collect was

 

(1/7)G

 

Let's be optimists. She did collect milk for 6 out of the 7 days. That is also a fraction (6/7). So, she actually collected

 

(6/7)G

 

You can see that the amount collected plus the amount she didn't collect is G.

 

(1/7)G + (6/7)G = ((1/7) + (6/7))G

                         = (7/7) G

                         = G.

 

I hope this helps you understand the problem.