Q:

A) 18 minutes | B) 19 minutes |

C) 22 minutes | D) 24 minutes |

Answer: C) 22 minutes

Explanation:

Explanation:

Let the two conditioners be A and B

'A' cools at 40min

'B' at 45min

Together = **(a x b)/(a + b)**

= (45 x 40)/(45 + 40)

= 45 x 40/85

= 21.1764

= **22 min** (approx).