Question

Sophia took a test with 21 questions. If she answered two sevenths of the questions​ correctly, how many did she get​ wrong?

Answer 1

She wronged 15 questions.

Explanation:

Given that she answer 2/7 correctly. So firstly, you have to calculate how many questions she answered correctly, you have to multiply it by 21 :

`(2)/(7) * 21 \\ = 6 \: questions`

She has answered 6 questions correctly then the remaining questions are wrong. So you have to substract from the correct answer :

`wrong = 21 - 6`

`wrong = 15 \: questions`

Answer 2

Sophia took a test with 21 questions.

If she answered two sevenths of the questions​ correctly, number of correct answers she did: N = 21 x 2/7 = 6

=> Number of answers she got wrong: N = 21 - 6 = 15

Hope this helps!

:)