Jasmine writes the following: 1/3 of 21 is 7. To find 2/3 of 21, You need to add on 1/3, so 2/3 of 21 is 7 1/3.
Jasmine is wrong. How would you explain her mistake to her. pls Show working out

In the next 10 month,colin wants to save $900 for his vacation.he plans to save $75 each of the first 8 months. how much must he save each of the last 2 months in order to meet his goal if he saves the same amount each month ?