Exercise 11.4
1. If three apples cost ₹45, how much would five apples cost?
The cost of 3 apples = ₹
Cost of 1 apple = ₹45 ÷
Cost of 5 apples = ₹15 ×
The cost of 5 apples is ₹75.
2. Laxmi bought 7 books for a total of ₹56. How much would she pay for just 3 books?
The cost of 7 books = ₹
Cost of 1 book = ₹56 ÷
Cost of 3 books = ₹8 ×
Laxmi would pay ₹24 for 3 books.
3. Reena wants to prepare vegetable pulao. she needs 300 grams of rice. If she has to feed 4 people. How much of rice is needed if the same pulao is prepared for 7 people?
4. The cost of 16 chairs is ₹3600. Find the number of chairs that can be purchased for ₹4500.
5. A train moving at a constant speed covers a distance of 90 km. in 2 hours. Find the time taken by the train to cover a distance of 540 km at the same speed.
The train covers 90 km in 2 hours.
Speed of the train = Distance ÷ Time
= 90 km ÷ 2 hours =
Now, to cover 540 km at the same speed:
Time = Distance ÷ Speed
= 540 km ÷
The train will take 12 hours to cover 540 km at the same speed.
6. The income of Kumar for 3 months is ₹15000. If he earns the same amount for a month.
7. If the cost of 7 meters of cloth is Rs 294, find the cost of 5m of cloth.
8. A farmer has sheep and cows in the ratio 8 : 3.
(i) How many sheep has the farmer, if he has 180 cows?
So, the farmer has 480 sheep.
(ii) Find the ratio of the number of sheep to the total number of animals the farmer has.
(iii) Find the ratio of the total number of animals with the farmer to the number of cows with him.
Are 3, 5, 15, 9 in proportion? If we change their order, can we think of proportional pairs? Write as many proportionality statements as you can for the above example?
Four numbers a,b,c,d are in proportion if:
Given numbers : 3,5,15,9 =
Calculate :
Since 0.6
Check if 3,9,5,15 are in proportion:
So, 3:9 :: 5:15.
Check if 5,15,3,9 are in proportion:
So, 5:15 :: 3:9.
Check if 15,3,9,5 are in proportion:
Check if 9,3,15,3 are in proportion:
So, 9:3 :: 15:5.
The temperature has dropped by 15 degree Celsius in the last 30 days. If the rate of temperature drop remains the same, how much more will the temperature drop in the next 10 days?
The temperature drop per day is:
In the next 10 days, the temperature will drop by: 0.5 × 10 =
The temperature will drop by 5°C in the next 10 days.
Fill in the following blanks:
12. (i) Ratio of breadth and length of a hall is 2: 5. Complete the following table that shows some possible breadths and lengths of the hall.
| Breadth of the hall(in m) | 10 | ? | 40 | ||
|---|---|---|---|---|---|
| Length of the hall(in m) | 25 | 50 | ? |
Add 2 more of your choice.
The missing breadth when length is 50m
The ratio is
Breadth =
The missing length when breadth is 40m
Length =
2 More additional values:
If Breadth = 16m , Length =
If Breadth = 30m , Length =
| Breadth of the hall(in m) | 10 | 40 | |||
|---|---|---|---|---|---|
| Length of the hall(in m) | 25 | 50 |
(ii) Find the ratio of length to breadth of your classroom.
For example, if Length = 6m and Breadth = 4m, then the ratio =
13. Geetha earns ₹12000 a month, out of which she saves ₹3000. Find the ratio.
Geetha's expenditure = Income - Savings = ₹12,000 - ₹3,000 = ₹
(i) Expenditure to savings
Ratio =
(ii) Savings to her income
Ratio =
(iii) Expenditure to her income
Ratio =
14. There are 45 persons working in an office. The number of females is 25 and the remaining are males. Find the ratio.
Number of males = Total Persons - Number of females =
(i) The number of females to number of males.
Ratio =
(ii) The number of males to the number of females.
Ratio =
A bag of sweets contain yellow and green sweets. For every 2 yellow sweets, there are 6 green sweets.Complete this table based on the above information.
| Yellow | 4 | 6 | |||
|---|---|---|---|---|---|
| Green | 6 | 12 | 18 | ||
| Total Sweets | 8 | 30 | 64 |
Now answer these questions.
(i) What is the ratio of green to yellow sweets :
(ii) If you have 8 yellow sweets, how many green sweets will you have : 8 ×
(iii) If there are 32 sweets in the medium sized bag. How many will be yellow :
(iv) In the super fat size bag there are 40 sweets. How many will be green :
(v) In the sweet bowl if there are 16 yellow sweets. How many total sweets are in the bowl: 16 + (16 × 3) =
16. In a school survey it was found that for every 4 girls there were 5 boys.
Fill in the following table.
| Girls | 4 | 8 | ||
|---|---|---|---|---|
| Boys | 25 | 20 | ||
| Total |
Now answer these questions:
(i) What is the ratio of girls to boys :
(ii) In a class of 27 children, how many would be girls:
(iii) There are 54 children in a class.How many are boys:
(iv) If 20 girls join in a year. How many boys would join?