Surface Areas & Volumes | Exercise 13.5 | Q6

Question 6: A village, having a population of 4000, requires 150 litres of water per head per day. It has a tank measuring 20 m x 15 m x 6 m. For how many days will the water of this tank last?

Explanatory Answer | Class 9 Math Exercise 13.5 Q6

Given Data

Population of the village = 4000
Water requirement per head per day = 150 litres
Dimensions of the tank = 20 m × 15 m × 6 m

Step 1: Compute the volume of the water tank

Volume of the tank = l × b × h
= 20 × 15 × 6 m³
= 1800 m³
1 m³ = 1000 litres
Water in the tank = 1800 × 1000 litres
Volume of water in the tank = 18,00,000 litres

Step 2: Compute number of days water will last for the entire population

Total water requirement per day = Population × Water required per person per day
= 4000 x 150
= 6,00,000 litres
Number of days the water will last = \\frac{\text{Capacity of tank}}{\text{Water requirement per day}})
= \\frac{18,00,000}{6,00,000}) = 3 days
The water in the tank will last 3 days.

Exercise 13.1 | Surface Area of Cubes & Cuboids

1. Class 9 Exercise 13.1 Question 3 | Height of hall ▶
2. Class 9 Exercise 13.1 Question 6 | TSA of Herbarium ▶
3. Class 9 Exercise 13.1 Question 7 | Shanti Sweets ▶

Exercise 13.2 | Surface Area of Cylinders

1. Class 9 Exercise 13.2 Question 3 | CSA TSA of Metal Pipe ▶
2. Class 9 Exercise 13.2 Question 4 | Roller & Playground ▶
3. Class 9 Exercise 13.2 Question 9 | Cylindrical Petrol Tank ▶
4. Class 9 Exercise 13.2 Question 10 | CSA of Decorative Lampshade ▶

Exercise 13.3 | Surface Area of Cones

1. Class 9 Exercise 13.3 Question 5 | Length of Tarpaulin 3 m wide ▶
2. Class 9 Exercise 13.3 Question 8 | Cost of painting conical barricades ▶

Exercise 13.4 | Surface Area of Spheres & Hemispheres

1. Class 9 Exercise 13.4 Question 8 | Outer CSA of hemispherical bowl ▶
2. Class 9 Exercise 13.4 Question 9 | Surface area of sphere & Cylinder ▶