Andrei has a glass tank. First, he wants to put in some marbles, each of which has a volume of 0.4 liters. Then, he wants to fill the tank with water until it's completely full. If he uses 50 marbles, he will have to add 33 liters of water.

What is the volume of the tank?
Andrei has exactly 20 liters of water. How many marbles does he need so the tank is full?

Respuesta :

lol at first i thought the question was a joke but now that u edited i think i got it

35 litters because  
0.04*50 is 2
2+33 is 35

Answer:

1)

First, he wants to put in some marbles, each of which has a volume of 0.4 liters.

Then, he wants to fill the tank with water until it's completely full.

If he uses 50 marbles, he will have to add 33 liters of water.

This means the volume of water that can be filled using 50 marbles is:

50×0.4=20 liters.

Also, total volume of tank is:

volume filled by 50 marbles+33 liters of water.

=20+33=53 liters.

Hence, Volume of tank=53 liters.

2)

If Andrei has exactly 20 liters of water.

Let n marbles be used.

Hence,

53=20+n×0.4

33=0.4n

n=33/0.4

n=82.5

Hence, she needs to use 83 marbles.