Question

8 pipes take 26 hours to fill a big drum. How long will 7 pipes take to fill the same drum?

• A. 29.7 hours
• B. 30.7 hours
• C. 28.7 hours
• D. 27.7 hours

Answer 1

The correct option is A 29.7 hours

Let the time taken by 7 pipes to fill the drum be t.
Note that as the number of pipes used decreases, the time taken to fill the drum increases. That is, the number of pipes used and the time taken to fill the drum are in inverse proportion.
Thus, we have 7 × t = 8 × 26
$⟹$ t = 29.7 hrs