A’s marks in Mathematics are directly proportional to practice time. In 6 hours of practice, A gets 70 marks. What should be the practice time (approximately) to get 90 marks?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 7.7 hours.
Marks ∝ Practice Time
Let a be the proportionality constant.
So, Marks = a × Practice Time
⇒ 70 = 6a
⇒ a = 70/6 = 35/3
Practice time to get 90 marks = 90/(35 / 3) = 270/35 = 7.714... ≈ 7.7 hours
Therefore, the practice time (approximately) to get 90 marks is 7.7 hours.