Question

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 ⅓.
Jasmine is wrong. How would you explain her mistake to her?

a) Jasmine didn't divide 21 by 3 before multiplying by 2.
b) Jasmine didn't subtract 1/3 from 7.
c) Jasmine didn't multiply 7 by 2/3
d) Jasmine didn't divide 21 by 2 before multiplying by 2/3.

Answer 1

Jasmine's mistake was not multiplying 7 by 2 to get 2/3 of 21; instead, she just added 1/3 to 7. The correct answer is 14, not 7 ⅓.

Step-by-step explanation:

Jasmine made a mistake in calculating 2/3 of 21. She correctly determined that 1/3 of 21 is 7, but her subsequent step to find 2/3 is where the error occurred. To find 2/3 of 21, Jasmine should multiply the value of 1/3 of 21 by 2. Therefore, the correct calculation is 7 (the result of 1/3 of 21) times 2, which equals 14. So, the correct answer for 2/3 of 21 is 14, not 7 ⅓ as Jasmine concluded.

The correct answer is given by explanation a) Jasmine didn't divide 21 by 3 before multiplying by 2. She did indeed divide 21 by 3 initially but made a mistake by not then multiplying 7 by 2 to find 2/3 of 21.