Question

A tank is fillied with 800 L water, the water in tank decreases by 25% of the total every hour. Which of the following data is correct regrading the function?

• A.

  Hours passed decreasing water level	Amount of water left in the tank
  0	800 L
  1	600 L
  2	450 L
  3	300 L

• B.

  Hours passed decreasing water level	Amount of water left in the tank
  0	800 L
  1	600 L
  2	400 L
  3	300 L

• C. None of the above
• D.

  Hours passed decreasing water level	Amount of water left in the tank
  0	800 L
  1	600 L
  2	450 L
  3	112.5 L

Answer 1

The correct option is D

Hours passed decreasing water level	Amount of water left in the tank
0	800 L
1	600 L
2	450 L
3	112.5 L

It is given that

$\text{The amount of water in the tank = 800 L}$

Percentage of water decreased by every hour is = 25 % from the total

At t = 0 hrs, amount of water = 800 L

$\text{At t = 1hr, amount of water = 800}\times 25\%=600$

$\text{At t = 2hrs, amount of water = 600}\times 25\%=450$

$\text{At t = 3hrs, amount of water = 450}\times 25\%=112.5$

We get:

Hours passed decreasing water level	Amount of water left in the tank
0	800 L
1	600 L
2	450 L
3	112.5 L