16. Solve -3x2 - 9x + 12 = 0.

Given :

To find :-

Solution :-

Given equation ,

Step-by-step explanation:

To obtain score of 80% on entire exam means the student have to answer

(80/100)×80 = 64 correct answers

Student have already answered 75% of the first 60 questions correctly meaning

(75/100)×60=45 correct answers from first 60 questions

Remaining correct answers s/he have to answer

64-45=19

So from remaining 20 questions s/he have to answer 19 correct questions that is

20 × (x/100) = 19

x = 19 ×(100/20)

x = 95%