CBSE Class 4 Subject Mathematics
NCERT Solutions
Chapter -6
THE JUNK SELLER
NCERT Solutions
Chapter -6
THE JUNK SELLER
1. What about you? Do you also find Maths difficult?
Ans. I do not find Maths difficult.
2. What is the most difficult thing in you Maths book?
Ans. The chapter entitled “The Way the World Looks” is the most difficult thing in Maths book.
3. What do you think is the easiest lesson?
Ans. The lesson “A Trip to Bhopal” is the easiest.
4. Find out: how much for a cup of tea?
Ask people and find out the cost of a cup of tea
(a) At a tea stall
Ans. (a) At a tea stall, the cost of a cup is Rs 3.
(b) At a hotel
Ans. (b) At a hotel, the cost of a cup is Rs 10.
5. If a person who runs a tea stalls earns Rs 30 in a day, how much will he earn in 10 days? And in a month? How did you get the answer? Discuss.
Ans. Earning of a tea stall owner per day = Rs 30
Therefore, earning of a tea stall owner in 10 days = Rs (10
30) = Rs 300
30) = Rs 300
And his, earning in a month = Rs (30 30) = Rs 900
30) = Rs 900
I got the answers by multiplication.
6. Find out: What is a loan?
(a) Have you ever heard of someone taking a loan? For what?
Ans. (a) Yes, I have heard of someone taking a loan. It is taken to buy a handcart.
(b) How much loan was taken?
Ans. (b) Rs 300 was taken as loan.
(c) How much money was paid back.
Hariya and Babu went to buy a handcart for Rs 300.
Ans. (c) Hariya: I have taken a loan of Rs 300 from a Bank for six months. I will pay Rs 51 every month to the bank.
Babu: But I have taken a loan of Rs 300 from Chunnilal. After six months, I will pay back Rs 360.
(d) Who has to pay back more- Hariya or Babu?
Ans. (d) In case of Hariya: Money paid back to the bank = Rs. 6 51 = Rs 306
51 = Rs 306
In case of Babu: Money paid back to Chunnilal = Rs 360
Since, Rs 360 is more than Rs 300, therefore, Babu paid back more money.
7. (a) I have 9 rickshaws of my own. I give the rickshaws on rent, each of Rs 20 a day. On Sundays I do not take any money from them? How much does Kiran earn from 9 Rickshaws in a Day?
Ans. (a) For 1 rickshaw she gets Rs 20 per day.
So, for 9 rickshaws she will earn Rs 180.
(b) How did you do it?
Ans. (b) I did it by multiplying 20 and 9 (20 9=180).
9=180).
8. In a week how much does Kiran earn from one rickshaw?
Ans. Since on Sundays Kiran does not take any money for rickshaw’s rent, therefore, Kiran earns in a week on one rickshaw at the rate of Rs 20 per day = Rs 6 20 = Rs 120.
20 = Rs 120.
9. Do it mentally and write the answers:
(a) 2 6= __
6= __
Ans. (a) 2 6= 12.
6= 12.
(b) 20 6 = __
6 = __
Ans. (b) 20 6 = 120.
6 = 120.
(c) 2 60 = __
60 = __
Ans. (c) 2 60 = 120.
60 = 120.
(d) 3 42 = __
42 = __
Ans. (d) 3 42 = 126.
42 = 126.
(e) 4 80 = __
80 = __
Ans. (e) 4 80 = 320.
80 = 320.
(f) 4 81 = __
81 = __
Ans. (f) 4 81 = 324.
81 = 324.
(g) 9 25 = __
25 = __
Ans. (g) 9 25 = 225.
25 = 225.
(h) 31 9 = __
9 = __
Ans. (h) 31 9 = 279.
9 = 279.
10. 4 81 is 4 more than 4 80. Am I right?
81 is 4 more than 4 80. Am I right?
Ans. Yes.
11. How much Kiran will pay for 31 kg newspaper?
Ans. Kiran will pay for 31 kg newspaper = Rs (51 30 + 5 1) = Rs 155.
30 + 5 1) = Rs 155.
12.
(a) How much Kiran pay for 42 kg newspaper?
Ans. (a) Kiran will pay Rs (42 5) = Rs 210.
5) = Rs 210.
(b) Also find the costs of:
(i) 22 kg of plastic
Ans. (b) (i) Cost of 22 kg of plastic = Rs (22 10) = Rs 220.
10) = Rs 220.
(ii) 23 kg of wastepaper
Ans. (b) (ii) Cost of 23 kg of newspaper = Rs (23 4) = Rs 92.
4) = Rs 92.
(iii) 12 kg of iron.
Ans. (b) (iii) Cost of 12 kg of iron = Rs (12 12) = Rs 144.
12) = Rs 144.
13. Can you do this without writing? Guess the total money Kiran will pay to the junk collectors. Will it be: More than 600? Less than 600?
Ans. Less than 600.
14. Kiran bought 1 kg of plastic for Rs 10, but sold 1 kg plastic for Rs 12. How much money does she earn on selling 63 kg plastic?
Ans. Earning on selling 1 kg of plastic = Selling price – Cost price = Rs 12 – Rs 10 = Rs 2
So, earning on selling 63 kg of plastic = Rs 2 Rs 63
Rs 63
60
|
3
|
60
2 |
3
2 |
120
|
6
|
On adding the numbers in the last row = 120 + 6 = 126.
So, for 63 kg of plastic, Kiran earns = Rs 126.
15. How much money will Dinu pay for 32 kg iron?
Ans. The rate of 1 kg of iron is Rs 14. So, the cost for 32kg of iron is Rs 14 32.
32.
We write as:
30
|
2
| |
10
|
30
10 |
2
10 |
300
|
20
| |
4
|
30
4 |
2
4 |
120
|
8
|
So, for 32 kg iron, Dinu will pay Rs 448.
16. Kiran buys 1 kg iron for Rs 12, but sells it for Rs 14. How much does she earn when she sells 32 kg iron?
Ans. Earning of selling 1 kg iron = Selling price -Cost price = Rs 14 – Rs 12 = Rs 2
So, earning on selling 32 kg of iron = Rs 2 32 of iron = Rs 2 32
32 of iron = Rs 2 32
We write as:
30
|
2
|
30
2 |
2
2 |
60
|
4
|
So, Kiran earns Rs 64 on the sale of 32 kg iron.
17. I bought 1 kg newspaper for Rs 5, but sold it for Rs 6. How much money did I earn by selling 152 kg of newspaper?
Ans. Rs 152.
18. How much money will Dinue pay for 4 kg brass? Guess the answer first.
Ans. The rate of 1 kg brass is Rs 170. So, the cost of 4 kg brass is Rs 170 4. We guess the answer to lie between Rs 600 and Rs 800.
4. We guess the answer to lie between Rs 600 and Rs 800.
We write as:
4
|
100
|
70
|
100
4 |
70
4 | |
400
|
280
|
So, for 4 kg brass Dinu will pay Kiran Rs 680.
19. First guess the answer then calculate:
(a) 37 18
18
Ans. (a) On guessing 37 18 may be = 740.
18 may be = 740.
We write as:
30
|
7
| |
10
|
30
10 |
7
10 |
300
|
70
| |
8
|
30
8 |
7
8 |
240
|
56
|
Adding the numbers = 300 + 240 + 70 + 56 = 666
So, 37 18 = 666.
18 = 666.
(b) 45 24
24
Ans. (b) On guessing 45 24 = 1080
24 = 1080
We write as:
40
|
7
| |
20
|
40
20 |
5
20 |
800
|
100
| |
4
|
40
4 |
5
4 |
160
|
20
|
Adding the numbers = 800 + 160 + 100 + 20 = 1080
So, 45 24 = 1080
24 = 1080
(c) 69 52
52
Ans. (c) On guessing 69 52 = 3588
52 = 3588
We write as:
60
|
9
| |
50
|
60
50 |
9
50 |
3000
|
450
| |
2
|
60
2 |
9
2 |
120
|
18
|
Adding the numbers = 3000 + 120 + 450 + 18 = 3588
So, 69 52 = 3588.
52 = 3588.
(d) 77 55
55
Ans. (d) On guessing 77 55 = 4235
55 = 4235
We write as:
70
|
7
| |
50
|
70
50 |
7
50 |
3500
|
350
| |
5
|
70
5 |
7
5 |
350
|
35
|
Adding the numbers = 3500 + 350 + 350 + 35 = 4235
So, 77 55 = 4235.
55 = 4235.
(e) 142 5
5
Ans. (e) On guessing 142 5 = 710
5 = 710
We write as:
100
|
40
|
2
| |
5
|
100
5 |
40
5 |
2
5 |
500
|
200
|
10
|
Adding the numbers = 500 + 200 + 10 = 710
So, 142 5= 710.
5= 710.
(f) 382 3
3
Ans. (f) On guessing 382 3 =1146
3 =1146
We write as:
300
|
80
|
2
| |
3
|
300
3 |
80
3 |
2
3 |
900
|
240
|
6
|
Adding the numbers = 900 + 240 + 6 = 1146
So, 382 3 = 1146
3 = 1146
(g) 2 175
175
Ans. (g) On guessing 2 175 = 350
175 = 350
We write as:
100
|
70
|
5
| |
2
|
100
2 |
70
2 |
5
2 |
200
|
140
|
10
|
Adding the numbers = 200 + 140 + 10 = 350
So, 2 175 = 350.
175 = 350.
(h) 4 206
206
Ans. (h) On guessing 4 206 = 824
206 = 824
We write as:
200
|
0
|
6
| |
4
|
200
4 |
0
4 |
6
4 |
800
|
0
|
24
|
Adding the numbers = 800 + 0 + 24 = 824
So, 4 206 = 824.
206 = 824.