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

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3

you already gave the answer

step-by-step explanation: