Ratio And Proportion

In a bag, there are coins of 25 p, 10 p and 5 p in the ratio of 1 : 2 : 3. If there is Rs. 30 in all, how many 5 p coins are there?

A:

50

B:

100

C:

150

D:

200

Answer: C

Let the number of 25 p, 10 p and 5 p coins be x, 2x, 3x respectively.

Then, sum of their values = Rs.		25x	+	10 x 2x	+	5 x 3x		= Rs.	60x
		100		100		100			100

	60x	= 30	x =	30 x 100	= 50.
	100			60

Hence, the number of 5 p coins = (3 x 50) = 150.

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Two number are in the ratio 3 : 5. If 9 is subtracted from each, the new numbers are in the ratio 12 : 23. The smaller number is:

A:

27

B:

33

C:

49

D:

55

Answer: B

Let the numbers be 3x and 5x.

Then,	3x - 9	=	12
	5x - 9		23

23(3x - 9) = 12(5x - 9)

9x = 99

x = 11.

The smaller number = (3 x 11) = 33.

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The fourth proportional to 5, 8, 15 is:

A:

18

B:

24

C:

19

D:

20

Answer: B

Let the fourth proportional to 5, 8, 15 be x.

Then, 5 : 8 : 15 : x

5x = (8 x 15)

x =	(8 x 15)	= 24.
	5

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If 40% of a number is equal to two-third of another number, what is the ratio of first number to the second number?

A:

2 : 5

B:

3 : 7

C:

5 : 3

D:

7 : 3

Answer: C

Let 40% of A =	2	B
	3

Then,	40A	=	2B
	100		3

	2A	=	2B
	5		3

	A	=		2	x	5		=	5
	B			3		2			3

A : B = 5 : 3.

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The salaries A, B, C are in the ratio 2 : 3 : 5. If the increments of 15%, 10% and 20% are allowed respectively in their salaries, then what will be new ratio of their salaries?

A:

3 : 3 : 10

B:

10 : 11 : 20

C:

23 : 33 : 60

D:

Cannot be determined

Answer: C

Let A = 2k, B = 3k and C = 5k.

A's new salary =	115	of 2k =		115	x 2k		=	23k
	100			100				10

B's new salary =	110	of 3k =		110	x 3k		=	33k
	100			100				10

C's new salary =	120	of 5k =		120	x 5k		= 6k
	100			100

New ratio		23k	:	33k	: 6k		= 23 : 33 : 60
		10		10

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Questions for: Ratio And Proportion