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# The waterlevel in the old aquarium is 60cm and while transferring the water to the new aquarium it lowers with 2cm per minute...

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The waterlevel in the old aquarium is 60cm and while transferring the water to the new aquarium it lowers with 2cm per minute.  In the new aquarium the waterlevel is already 8cm and it rises with 1,25cm per minute.

A. Show with calculations that after 5 minutes the waterlevel in the old aquarium is 50cm and the new one is 14,25.

B. Make for both aquariums a formula for the connection between waterlevel and time the pump is on. Take W for waterlevel and T for the time in minutes.

C. To put fishes in the new aquarium its waterlevel must be more than the old aquariums waterlevel. What inequality belongs to this?

D. Solve the inequality from C.

E. What does solution mean

F. Calculate the waterlevel of the new aquarium after all the water of the old aquarium is transferred to the new aquarium

Sorry my first language isn't english, I had to translate the questions.

Feb 2, 2018

#2
+8963
+3

A.

60 cm  -  2 cm/min *  5 min   =   60 cm - 10 cm   =   50 cm

8 cm  +  1.25 cm/min * 5 min   =   8 cm  +  6.25 cm   =   14.25 cm

B.

water level of old aquarium  =  W  =  60 - 2T

water level of new aquarium  =  W  =  8 + 1.25T

C.

water level of new aquarium  >  water level of old aquarium

8 + 1.25T  >  60 - 2T

D.

8 + 1.25T  >  60 - 2T

3.25T  > 52

T > 16

E.

The new aquarium's water level will be greater than the old aquarium's water level after  16  mins.

F.

Find the time it takes for the water level of the old aquarium to be  0  .

0  =  60  - 2T

2T  =  60

T  =  30

Find the water level of the new aquarium at this time.

W  =  8 + 1.25(30)

W  =  45.5

Feb 2, 2018
edited by hectictar  Feb 2, 2018

#1
+111331
+1

.........

Feb 2, 2018
edited by CPhill  Feb 2, 2018
edited by CPhill  Feb 2, 2018
#2
+8963
+3

A.

60 cm  -  2 cm/min *  5 min   =   60 cm - 10 cm   =   50 cm

8 cm  +  1.25 cm/min * 5 min   =   8 cm  +  6.25 cm   =   14.25 cm

B.

water level of old aquarium  =  W  =  60 - 2T

water level of new aquarium  =  W  =  8 + 1.25T

C.

water level of new aquarium  >  water level of old aquarium

8 + 1.25T  >  60 - 2T

D.

8 + 1.25T  >  60 - 2T

3.25T  > 52

T > 16

E.

The new aquarium's water level will be greater than the old aquarium's water level after  16  mins.

F.

Find the time it takes for the water level of the old aquarium to be  0  .

0  =  60  - 2T

2T  =  60

T  =  30

Find the water level of the new aquarium at this time.

W  =  8 + 1.25(30)

W  =  45.5

hectictar Feb 2, 2018
edited by hectictar  Feb 2, 2018
#3
+111331
+1

.......

Feb 2, 2018
edited by CPhill  Feb 2, 2018