Multiple choice

Anil has taken 50 tests in a school and passed some of them, getting test passing average of 20%. Find the number of more tests that he must pass to attain test passing average of 60%; and he has passed every test after 50 tests.

  1. 30

  2. 40

  3. 50

  4. 60

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Anil passed 20% of 50 = 10 tests. Let x be the number of additional tests. Total tests = 50 + x. Passed tests = 10 + x. We want (10 + x) / (50 + x) = 0.6. 10 + x = 30 + 0.6x => 0.4x = 20 => x = 50.

AI explanation

Let the number of additional tests Anil must pass be y, so his total passed tests become 50 + y. Setting up the equation for the test passing average, 20 percent of 50 plus 100 percent of y equals 60 percent of the total tests (50 + y). This gives 10 + y = 0.6(50 + y), which simplifies to 10 + y = 30 + 0.6y, so 0.4y = 20. Solving for y gives 50, meaning he must pass 50 more tests.

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