Page 116 - ICSE Math 6

Example 14: Sonali pays ` 9,000 as rent for 5 months. How much will she pay for a whole year, if
the rent per month remains the same?

Solution: Rent for 5 months = ` 9,000
9,000
Rent for 1 month = ` = ` 1,800
5
\ Rent for 1 year = ` 1,800 × 12 = ` 21,600.

EXERCISE 8.3

1. If the cost of 6 soaps is ` 54, find the cost of 10 such soaps.

2. Sia covers a distance of 70 m in 90 equal steps. What distance will she cover in 270 steps?
3. If 45 kg of paper is required to make 500 notebooks, then how much paper is required to make
700 such notebooks?

4. A car uses 30 litres of petrol to cover a distance of 375 km. How many litres of petrol will it use
to cover a distance of 1,200 km?

5. An alloy is formed by mixing 4.5 g copper and 2.8 g zinc. How much alloy of similar kind can
be formed by using 13.5 g copper?
6. A transport company charges per box to carry fifteen to twenty-five boxes. If it charges ` 2,000
to carry 25 boxes, how much will it charge to carry 18 boxes?

7. The weight of 12 chairs is 60 kg. What will be the weight of 18 such chairs?
8. Ajay earns ` 10,680 in 12 days. How much will he earn in 18 days?

AT A GLANCE

¾ Ratio is the relation obtained between two quantities (of the same kind and of the same unit) by
dividing one quantity by the other.
¾ If a given quantity ‘a’ is divided in the ratio x : y, then

 x   y 
First part =   ×a and Second part =   ×a
 x + y   x + y 

¾ When two ratios are equal, they are said to be in proportion.
¾ In unitary method, the value of a unit quantity is obtained to find the value of the required
quantity.

MENTAL MATHS

1. Fill in the blanks.
(a) For the ratio 6 : 11, the antecedent is _________ and the consequent is _________.

(b) For the ratio 13 : 2, the first term is _________ and the second term is _________.
(c) For the proportion, 2 : 9 : : 10 : 45, extreme terms are _________ and _________, and mean
terms are _________ and _________.

100