An aquarium tank can hold 6600 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 66 minutes. The
second pipe can fill the tank in 55 minutes by itself. When both pipes are working together, how long does it take them to fill the tank?
U minutes
X
5
?

The first pipe operates at rate of (6600 L / 66 min) = 100 L/min.

The second pipe operates at a rate of (6600 L / 55 min) = 120 L/min.

Working together, both pipes operate at a total rate of 220 L/min.

Then the time it takes for both of them to fill the tank is

(6600 L) * (1/220 min/L) = 30 min

34.5 cm

step-by-step explanation:

generally for a circular segment of angle, θ° and radius r

arc length

= (θ/360) x circumference

= (θ/360) x 2πr

in our case, θ = 60°, π=3.142 and r = 33 cm

substitute into above formula

arc length

= (60/360) x 2(3.142)( 33) = 34.5 cm