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Re: Among the students who took maths and physics test,
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30 Mar 2023, 09:22
Let's assume that there are 100 students who took both Math and Physics tests.
Then, 4/5 of the students did not fail in Math, which means that 1/5 of the students failed in Math, or 20 students failed in Math.
Of the 80 students who did not fail in Math, 2/3 of them did not fail in Physics. Therefore, the number of students who did not fail in both Math and Physics is:
80 × 2/3 = 160/3
So the number of students who failed in at least one of the exams is:
20 + 100 - 160/3 = 220/3
Therefore, the fraction of the number of students who failed in at least one of the exams is:
220/3 ÷ 100 = 22/3 ÷ 10 = 22/30 = 11/15
So the answer is option (B) 7/15.