87
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).