# Ratio and Proportion - Aptitude Questions and Answers Part 2

6. a:b = 3:4 and b:c = 9:7. What is a:b:c?

a. 3 : 13 : 7
b. 3 : 36 : 28
c. 27 : 16 : 28
d. 27 : 36 : 28

Answer: d. 27 : 36 : 28

Explanation:

B is common to both the ratios.
Values of b = 4 and 9 (That means they are not the same)
Make the values of 'b' same as follows -
Multiply 3:4 up and down with 9 as shown

 ∴ 3 x 9 = 27 = a 4 x 9 36 b
Multiply 9:7 up and down with 4 as shown
 ∴ 9 x 4 = 36 = b 7 x 4 28 c
Since, values of b are same = 36
a : b : c = 27 : 36 : 28

7. Ram saves Rs 3395/- from his salary. He needs to pay this money as milk bill, electricity bill and mobile phone bill in the ratio 42 : 32 : 23. Find the money to be paid for each bill.

a. Rs 1245/-, Rs 1150/- and Rs 1000/-
b. Rs 1470/-, Rs 1120/- and Rs 805/-
c. Rs 1550/-, Rs 1235/- and Rs 610/ -
d. Rs 1764/-, Rs 1022/- and Rs 529/-

Answer: b. Rs 1470/-, Rs 1120/- and Rs 805/-

Explanation:

Common factor helps in finding actual values easily
So, take 'A' as common factor.
∴ 3 numbers will now be 42A, 32A and 23A
∴ 42A + 32A + 23 A = 3395
∴ 97A = 3395
∴ A = 35
3 parts of 3395 are
42A = 42 x 35 = 1470;
32A = 32 x 35 = 1120
23A = 23 x 35 = 805
These are the amounts to be paid.

8. Three numbers add up to 285 such that the ratio between first two numbers is 3:7 while the ratio between second and third number is 6:5. Find the value of the second number.

a. 124
b. 126
c. 135
d. 150

Explanation:

 1st number : 2nd number = 3:7 = 3 7
 2nd number : 3rd number = 6:5 = 6 5
Values of 2nd number = 7 and 6 (They are not the same)
Make the values of 2nd number same as follows -
Multiply 3:7 up and down with 6 as shown
 ∴ 3 x 6 = 18 = 1st Number 7 x 6 42 2nd Number
Multiply 6:5 up and down with 7 as shown
 ∴ 6 x 7 = 42 = 2nd Number 5 x 7 35 3rd Number
Values of 2nd number are now same = 42
1st number : 2nd number = 18 : 42
2nd number : 3rd number = 42 : 35
1st number : 2nd number : 3rd number = 18 : 42 : 35
Common factor helps in finding actual values easily
So, take 'A' as common factor.
So now the 3 numbers are 18A, 42A and 35A
∴ 18A + 42A + 35A = 285
∴ A = 3
2nd number = 42A = 42 x 3 = 126

9. Ram and Shyam were carrying some money such that their money was in the ratio 3:8. A friend gives each of them Rs 5/- and their money is now in the ratio 2:5. Which is the smaller money of the two?

a. 45
b. 64
c. 105
d. 120

Explanation:

Ratio of original money numbers = 3:8
Common factor helps in finding actual values easily
So, take 'M' as common factor.
∴ Original numbers will be 3M and 8M
Adding 5 to them, we get (3M + 5) and (8M+5)

 ∴ 3M+5 = 2 -----------------> (Ratio of new numbers is 2:5) 8M+5 5
∴ 15M + 25 = 16M + 10
∴ M = 15
Smaller money value is 3M = 3 x 15 = 45

10. In a pitcher carries a mixture of alcohol and water for a party in the ratio 4:3 but the pitcher is still empty. If 2 bottles of water 3 litres and 2 litres respectively are emptied in the pitcher, the ratio changes to 4:5. How much alcohol does the mix contain?

a. 7.5 Ltr
b. 8 Ltr
c. 12 Ltr
d. 16 Ltr