Multiple choice

A filling pipe can fill a empty tank in 15 hrs while draining pipe can empty the same tank in 25hrs.If a system of n pipes including filling and draining pipes an fill an empty pool in 5 hrs. And if n is neither less than nor Greater than 43 , then which of the following is true

  1. more than 20 filling pipes were installed

  2. Less than 19 filling pipes were installed

  3. Number of draining pipes was 7 more than the filling pipes

  4. More than one is true
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Interpreting the condition as n = 43, let f be the number of filling pipes and d the number of draining pipes. Solving f + d = 43 and f/15 - d/25 = 1/5 gives f = 18 and d = 25. Thus fewer than 19 filling pipes were installed, and the draining pipes were 7 more than the filling pipes, so more than one statement is true.

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