Page 98 - ICSE Math 8

3. Divide ` 1,000 in the ratio 3.5 : 6.5.
4. Is 7 : 9 :: 35 : 49 a proportion?
5. Find the value of x, if 8 : 15 :: 16 : x.
6. Write True or False.
(a) To determine a ratio, the two quantities should be of the same kind but can have different units.
(b) In inverse proportion, an increase in the first quantity causes a decrease in the second quantity.
(c) In a proportion, if the fourth term is greater than the third term, then the second term may not be
greater than the first term.
(d) In a proportion, the product of extremes may or may not be equal to the product of means.

PRACTICE TIME

1. Which of the following ratios is greater?
3 2 1 4 2 3
(a) 2.63 : 5.78 or 7 : 12 (b) 2 : 1 or 2 : 1 (c) 3 : 2 or 17.2 : 12.5
4 5 3 5 5 4
2. Two numbers are in the ratio 6 : 7. If the first number is 16.8, find the second number.
3. A factory had 950 workers and the ratio of men to women was 11 : 8. When 50 male workers and some
female workers left the factory, the ratio became 25 : 16. Find the number of women who left the factory.
4. If A : B = 9 : 11 and B : C = 13 : 15, determine the following.
(a) A : B : C (b) A : C
5. If 7A = 12B = 19C, find A : B : C.
6. Find the following.
(a) Fourth proportional to 2.6, 7.4 and 11 (correct to two decimal places)
(b) Mean proportional between 170 and 153 (correct to three decimal places)
(c) Third proportional to 2.9 and 11.6

(d) Mean proportional between 8 and 6 (correct to three decimal places)
7. 54 men can complete a work in 32 days. In how many days will 36 men complete the same work?
8. A camp has medical supplies for 84 days. After 20 days, 400 more soldiers join the camp and the medicines
will now last for only 48 days. How many soldiers were there in the camp?
9. 6 pairs of socks cost ` (3x + 11) and 9 pairs of socks cost ` (5x + 6). Find the value of x.
2 1 9
10. Divide 10,076 into three parts in the ratio 2 : 3 and 2 .
7 4 14
11. There are some apples, bananas and oranges in a basket in the ratio 2 : 4 : 3. If the number of oranges is
15, find the number of apples and bananas.
12. Ria has ` 5, ` 2 and ` 1 coins in the ratio 1 : 3 : 5. If the total value of all the coins is ` 272, find the
number of each type of coins.

THINK SMART

Sarvan, Shikha and Akanksha divide an amount of ` 2,800 among themselves in the ratio 5 : 6 : 3 respectively.
If an amount of ` 200 is added to each of their shares, what will be the new ratio of their new shares?

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