Question

Li uses 8.4 grams of sugar every day in her tea. Sue uses 12.6 grams of sugar every day in her coffee. If Li’s sugar canister contains 128 grams of sugar and Sue’s canister contains 191 grams, in how many days will Li and Sue have the same amount of sugar in their canisters?

Answer 1

They will have the same amount of sugar in their canisters in 15 days

Explanation:

Here in this question, we are concerned with knowing the number of days in which the amount of sugar in both canisters will be the same.

Since we do not know the number of days it will take, we have to represent it using a variable.

Let the number of days be x days

Now, we are told Li uses 8.4 g per day.

So in x days, the amount user will be 8.4 * x = 8.4x g

Thus, the amount of sugar remaining in her canister after x days will be 128 - 8.4x

For Sue, she uses 12.6 grams each day. So in x days, the amount of sugar used will be 12.6 * x = 12.6x g

So the amount of sugar left in her canister will be 191-12.6x

Since on the xth day , the amount of sugar remaining is same, we can equate the amount of sugar remaining in both canisters. That would be;

128-8.4x =191-12.6x

Collect like terms;

12.6x-8.4x = 191-128

4.2x = 63

x = 63/4.2

x = 15 days