In a test (+2) marks are given for every correct answer and (-1) mark is given for every incorrect answer. Soumya answered all the questions and her score was 30 marks though she got 20 correct answers. How many of her answers were incorrect?

Given: 

In a test $(+2)$ marks are given for every correct answer and $(-1)$ mark is given for every incorrect answer.

Soumya answered all the questions and her score was $30$

She got $20$ correct answers.

To do: Find how many of her answers were incorrect.

Solution:

Number of questions answered correctly = $20$

Marks given for correct question = $+2$

So, Marks obtained for correct questions = $20 \times 2 = 40$

 Number of questions answered wrongly = $x$

Marks given for incorrect question = $-1$

So, Marks obtained for incorrect questions = $x \times (-1) = -x$

Total marks obtained in exam =  Marks obtained for correct questions $+$ Marks

Obtained for incorrect questions

$30  =  40 - x$ 

$x  =  40 - 30$

$x  = 10$

So, number of incorrect answers  = 10

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Updated on: 10-Oct-2022

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