Direct and Inverse Proportion Class 8 MCQ Questions

Answer: (c) 1200 km

Explanation: ​

Let the map distance between the two countries be M meter and the actual distance between two countries be N meter , then
we are given that,

M : N = 1 : 400000

M/N = 1/400000

The two countries are 3 meter apart ,

i.e., M = 3 meter

Substituting the value of M in given equation

3/N = 1/400000

N = (400000/1) x 3

N = 1200000 meter

N = 1200 Km

Thus, if the two countries which are 3 meter apart on map, the actual distance between them would be 1200 Km

Answer: (c) 0.8 Kg

Explanation: Total quantity of food = 4 Kg

Total calories in the food = 25000

So, ratio of calories to food = 25000/4

Let, there be m Kg of food which contains 5000 calories

So, ratio of calories to food = 5000/m

We are given that the ratio of calories to the weight of food are same.

Then, 25000/4 = 5000/m

m = (5000/25000) x 4

m = 0.8 Kg

Therefore, 0.8 kg of food will contain 5000 calories

Answer: (c) ​40000

Explanation: ​

Total quantity of food = 4

Total calories in the food = 20000

So, ratio of calories to food = 20000/4

Let, there be m calories in 8 Kg food

So, ratio of calories to food = m/8

We are given that the ratio of calories to the weight of food are same.

Then, 20000/4 = m/8

m = (20000/4) x 8

m = 40000 calories

Answer: (b) ​42 cm

Explanation: ​

Assuming that the ratio of the length to height of the model, will be the same ratio of the actual length to actual height of the car . So suppose the actual length of car is M

Ratio of length to height of the model = 36/48 = 3/4

Ratio of the actual length to the actual height of the car will be = M/56

Since both the proportions are same, the two ratios should be equal:

3/4 = M/56

M = (3/4) x 56

= 42 cm

If actual height of car is 56 cm then the actual length of the car is 42 cm

Answer: (a) 50 cm

Explanation: et the length of the map required be = M cm

Given, if map length is 10 cm then, area of length is 100 km.

Ratio of length of the map to length of the area = 10/100

Ratio of length of the map required to the length of the city = M/500

Ratio of length of the map to length of the area , should be in proportion with the length of the map required to the length of the city

or

10/100 = M/500

M = (10/100) x 500

M = 50

So the length of the map required for given area = 50 cm

Answer: (a) ​540 Km

Explanation: Speed of the car = Distance/Time

Speed of the car = 45/15 = 3/1 Km per minute

Minutes in 3 hours = 3 x 60 = 180 minutes

So Distance traveled = Speed x Time = (3/1) x 180

= 540 Km

If speed remains the same then the car can travel 540 Km in 3 hours