Ratio and proportion questions to try out

This article is in continuation to the last article focusing on the ratio and proportion topic. Here are some practice questions along with solutions that will help you in your preparation for the State government recruitment tests.

An alloy A is formed by mixing gold and silver in the ratio 2 : 1. Another alloy B is formed by mixing silver and platinum in the ratio 3 : 4. An alloy C is obtained by mixing alloys A and B in a certain ratio such that the ratio of gold and platinum in alloy C is 5 : 6. Which of the following correctly represents the share of silver in alloy C?

a) 17/31 b) 49/126
c) 29/51 d) 19/35

Ans: b

Solution: We have been given that alloy A contains gold and silver in the ratio 2 : 1.
Let there be 21x units of A.
So, it will have 14x units of gold and 7x units of silver. Let there be 21y units of alloy B.
So, we have 9 units of silver and 12 units of platinum.
Let these two be mixed to get the desired alloy.
Hence, the total amount of gold in alloy C will be 14x and total amount of platinum will be 12y.
We have been given that
14x/12y = 5/6
=> 84x = 60y
=> x/y = 5/7
Thus alloys A and B must have been mixed in the ratio
5 : 7
Thus, the share of silver in the final mixture
35 + 63 /252
= 98/252
= 49/ 126

Three friends Aravind, Bharat and Chandu are about to have their breakfast. Aravind has 7 apples, Bharat has 5 apples and Chandu has no apples but has 12 coins. He offers to pay for some apples. They agree to share the 12 apples equally among themselves and agree that Chandu would pay 12 coins for his share. Bharat suggests that he be paid 5 coins and Aravind be paid 7 coins. Aravind says that he should get more than 7 coins. How much should Aravind get?

a) 7 coins b) 9 coins
c) 11 coins d) 13 coins

Ans: b

Solution: As they together have 12 apples, each person gets a share of 4 apples.
Chandu took 4 apples as his share and paid 12 coins of the 4 apples.
1 apple is given by Bharat and 3 apples are given by Aravind.
The ratio of apples of Aravind and Bharat = 3 : 1.
They must be paid in that ratio i.e., 3 : 1
Hence, the number of coins that Aravind should get 3 × 12 / 4 = 9 coins

 

A bag contains certain number of coins of different denominations. The ratio of the number of Rs 1 coins to Rs 2 coins is 5 : 7, respectively and the ratio of number of Rs 2 coins to Rs 5 coins is 7 : 6 respectively. Find the total value of the Rs 5 coins, if the total value of the Rs 1 coins in the bag is Rs 15.

a) Rs 90 b) Rs 120
c) Rs 135 d) Rs 140

Ans: a

Solution: Ratio of the number of coins of denominations Rs 1 : Rs 2 : Rs 5 = 5 : 7 : 6
Let, the number of coins of Rs 1, Rs 2 and Rs 5 in the bag be 5x, 7x and 6x.
Since, the total value of Rs 1 coin in the bag is Rs 15
So, the number of coins of Rs 1 in the bag = 15
5x = 15
=> x = 3
Therefore, number of Rs 5 coins in the bag
= 6x = 18
So, required value of Rs 5 coins
= 6 × 3 × 5
= Rs 90

 

M Venkat
Director
MVK Publications
Dilsukhnagar
7671002120