Page 141 - Start Up Mathematics_7

2. In a city, 30% of the population are females, 40% are males and remaining are children. What
is the percentage of children?
What is the importance of saving a girl child?

3. Mrs Krishnamurthy saves 18% of her salary. If she saves ` 3,960 per month, what is her actual
salary?
What is the importance of saving money?

Some NCERT Textbook Questions

1. In a computer lab, there are 3 computers for every 6 students. How many computers will be
needed for 24 students?
2. Population of Rajasthan = 570 lakhs and population of UP = 1660 lakhs. Area of Rajasthan
2
2
= 3 lakh km and area of UP = 2 lakh km .
2
(i) How many people are there per km in both these states?
(ii) Which state is less populated?
3. In a city, 30% are females, 40% are males and remaining are children. What per cent are
children?
4. Meeta saves ` 400 from her salary. If this is 10% of her salary. What is her salary?
5. The population of a city decreased from 25,000 to 24,500. Find the percentage decrease.

6. Juhi sells a washing machine for ` 13,500. She loses 20% in the bargain. What was the price
at which she bought it?
7. Find the amount to be paid at the end of 3 years in each case:
(a) Principal = ` 1,200 at 12% p.a. (b) Principal = ` 7,500 at 5% p.a.

8. What rate gives ` 280 as interest on a sum of ` 56,000 in 2 years?

Exemplar Problems

1. The interest on ` 5,000 at the rate of 15% per annum for one month is:

(a) ` 750 (b) ` 75 (c) ` 625 (d) ` 62.50
2. A farmer bought a buffalo for ` 44,000 and a cow for ` 18,000. He sold the buffalo at a loss
of 5% but made a profit of 10% on the cow. The net result of the transaction is:

(a) loss of ` 200 (b) profit of ` 400 (c) loss of ` 400 (d) profit of ` 200
3. 20% of 700 m is:

(a) 560 m (b) 70 m (c) 210 m (d) 140 m
4. If 90% of x is 315 km, then the value of x is:

(a) 325 km (b) 350 km (c) 405 km (d) 340 km
5. 0.05 is equivalent to 5%. (True/False)

6. Suhana sells a sofa set for ` 9,600 making a profit of 20%. What is the C.P. of the sofa set?
3 9
7. A student said that the ratios and were proportional. What error did the student make?
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