1Is the relation between the length of the diameter of a circle and the measure of its circumference direct variation or indirect variation?
2What kind of relation is there between the number of students in a hostel and the number of days a fixed stock of food will last?
3At a fixed time and a fixed rate of interest, what kind of relation is there between the principal deposited and the interest earned?
4What kind of relation is there between the speed of a vehicle and the distance it covers?
5What kind of relation is there between the speed of a vehicle and the time it takes to cover a fixed distance?
6If four dozen pens cost Rs 576, how many pens can be bought for Rs 228?
7A runner can cover 18 km in 45 minutes. How long will the same runner take to cover 30 km?
8A goods truck covers a certain distance in 6 hours at 48 km per hour. If its speed falls to 36 km per hour, in how many hours will it cover that distance?
9A job takes 20 workers 15 days. How many extra workers are needed to finish the same job in 12 days?
10A job takes 12 people 14 days. If the number is raised to 21 people, in how many days will the job be finished?
11A barracks has rations enough for 200 soldiers for 30 days. How many soldiers must be moved elsewhere so that the rations last 40 days?
12A motorcycle takes 6 hours to cover a certain distance at 30 km per hour. If it must cover that distance in 5 hours, by how much must its speed be raised?
13Three chairs and four tables cost Rs 7,540 altogether. If one chair costs Rs 220, find the cost of one table.
14Five cows and two oxen cost Rs 1,35,000 altogether. If one ox costs Rs 17,500, what is the cost of one cow?
15If four people earn Rs 28,000 in 10 days, how much does one person earn in one day?
16Four people earn Rs 28,000 in 10 days. How much will three people earn in 15 days?
17By what percentage is the income of three people in 15 days more or less than the income of four people in 10 days?
18If 48 people need 700 kg of rice for 30 days, how much rice will 40 people need for 36 days?
19At Rs 60 per kilogram, what will the rice for 40 people for 36 days cost altogether?
20Fifteen people build a wall 50 metres long in 8 days. How many metres of wall will 16 people build in 12 days?
21Twenty people build an 80 metre wall in 8 days. How many people are needed to build a 60 metre wall in 24 days?
22Bhargav deposits Rs 6,000 in a bank for three years and receives Rs 1,800 as interest at the end of the three years. At the same rate of simple interest, how much interest will Rs 10,000 earn in four years?
23Six men and eight boys can cut the crop on 30 ropani in 4 days. If four boys can cut as much as two men, how much can 14 men and 8 boys cut in 8 days?
24Ten people working 7 hours a day build a road in 2 days. At how many hours a day must 5 people work to build a road of the same size in 14 days?
25Eighteen people can build a 54 metre wall in 10 days. How many people of the same ability are needed to build a 66 metre wall in 22 days?
26Twenty people take 25 days to make a park 40 m long and 20 m wide. How many days will 50 people take to make a park 50 m long and 40 m wide?
27If 25 people earn Rs 5,00,000 in 30 days, how much does one person earn in one day?
28If 25 people earn Rs 5,00,000 in 30 days, how many people will earn Rs 5,00,000 in 10 days?
29How many days will 25 people take to earn Rs 1,00,000?
30How much will five people earn in 40 days?
31Thirty people build a 600 m wall in 20 days. How much wall will 15 people build in 18 days? State at each step whether the relation is direct or indirect.
32Painting six houses in 24 days needs 32 people. How many extra people are needed to finish the same work in 8 days?
33Ten people working 8 hours a day built a shelter in 14 days. How many hours a day must 7 people work to build a shelter of the same size in 16 days?
34Six exercise books cost Rs 270. What will eleven exercise books cost? Solve it by the unitary method.
35Explain why the number of people put on one job multiplied by the number of days they take always stays the same.