Question

In an examination, 70% students passed in Physics, 80% students passed in Chemistry, 75% students passed in Mathematics and 85% students passed in Biology, and x% students failed in all the four subjects. What is the minimum value of x?

• A. $10$
• B. $12$
• C. $15$
• D. None of the above

Answer 1

The correct option is C $15$

$30\%$ student failed in PHY

$20\%$ student failed in CHEM

$25\%$ student failed in MATHS

$15\%$ student failed in BIO

To find minimum value of '$x$'

we can have all the above cases disjoint.

That is, if no student failed in more than 1 subject, we have venn diagram.

So $x_{min}=0$

Since $30+20+25+15<10$