Question

An air conditioner can cool the hall in 40 miutes while another takes 45 minutes to cool under similar conditions. If both air conditioners are switched on at same instance then how long will it take to cool the room approximately ?
A) 18 minutes
B) 19 minutes
C) 22 minutes
D) 24 minutes

Answer 1

heya !

Question -

An air conditioner can cool the hall in 40 miutes while another takes 45 minutes to cool under similar conditions. If both air conditioners are switched on at same instance then how long will it take to cool the room approximately ?

A) 18 minutes
B) 19 minutes
C) 22 minutes
D) 24 minutes

Answer -

Option C "22 minutes "

Let the two conditioners be A and B
'A' cools at 40min
'B' at 45min
= (a x b)/(a + b)
= (45 x 40)/(45 + 40)
= 45 x 40/85
= 21.1764
= 22 minutes [approximately]

hope this helps you !

Answer 2

Answer:

avg. / no. of ac = ((40+41)/2) / 2 = 42.5/2=~21.25(approx.), so answer is 22 min.

Step-by-step explanation: