Question

1 point
Q19 120 litres of water is drained
out of a water tank containing 400
litres of water. The percentage
decrease in the amount of water is​

Answer 1

Answer:

30% water decreased

Step-by-step explanation:

So we will go with both practical and theoretical method.

1) Practically

Here, total amount of water is 400%, so basically 10% of 400 will be 40. So here we are given 120 litres is drained so 40 × 3 = 120 therefore 10 × 3 = 30%.

With some practice you can easily approximate this kind of problems

2) By formula

percentage of water decreased =

=(amount of water decreased × 100) / total amount of water

= 120 × 100 / 400

= 12000/400

= 30%

Therefore percentage of water remaining is 70%.

I hope you are satisfied.

Answer 2

step by step explanation:- 400/120×100

means

400/12×10 why because 00 is cut

then 400/12=0.03

now,

0.03×10=0.3%

answer is 0.3%