Class 4    Math    Learn Liquid Units

Amount of water left in the bigger tank after filling smaller tanks

Question: Steve has 10 liters (L) tank filled with water. He wants to transfer the water in few smaller tanks of following sizes: 2 talks of 1.5 liters, 3 tanks of 750 ml and 6 tanks of 500 ml. Please calculate the amount of water left in 10 L tank after filling all the smaller talks ?

Answer: This is a pretty simple question. First we need to add capacity of all the smaller tanks. If the addition value of all the smaller tanks is less that 10 L, then subtract this value (addition value of smaller tanks) with 10 L and remaining value will be the answer. That is water left in the bigger tank.

On the other hand, if the addition value of all the smaller tanks will be greater than 10 L, then after subtraction, we will identify amount of water left to fill the all the smaller tanks.

Let us calculate capacity of all smaller tanks, which is:

     1.5 liters x 2 tanks = 3 liters
     750 ml x 3 tanks = 2250 ml = 2 liters and 250 ml
     500 ml x 6 tanks = 3000 ml = 3 liters

Now add all of the tanks, that is: 3 liters + 2 liters 250 ml + 3 liters = 8 liters and 250 ml, which can also be written as: 8 L and 250 ml

Now we will subtract 8 liters and 250 ml from 10 liters to calculate the rest amount of water in the bigger tank.

     So, 10 L − 8 L and 250 ml
     Or, 10,000 ml − 8250 ml
     = 1750 ml or 1 liter and 750 ml will be remaining in the 10 L tank

There is another way to solve this question. In this case we will fill first tanks first then from the remaining water we will second tank till we fill all the tanks. This way water left in the 10 L tank after filling all the tanks will be the answer. Something like below:

First, we have 2 tanks of 1.5 liters each, so total amount of water these two tanks contain = 2 x 1.5 = 3 L

So, the amount of water left after filling 2 tanks will be: 10 L − 3 L = 7 L

Next, we have 3 tanks of 750 ml each, so total water these three tanks will have = 3 x 750 ml = 2250 ml = 2 L and 250 ml (or 2.25 L)

Let us fill all these 3 tanks and calculate how much amount of water will be left. We can calculate this by subtracting 2L and 250 ml from 7L, something like this:

Water left after filling all 750 ml tanks = 7 L − 2.25 L = 4.75 L

Then, we have 6 tanks of 500 ml each, so the total volume is: 6 x 500 ml = 3000 ml = 3 L. So the water left after filling all 6 tanks will be: 4.75 L − 3 L = 1.75 L

1.75 L is nothing but 1 liter and 750 ml (answer)