Ratio and Proportion Test - 3

Given ratio = 6:4:10= 3:2:5

the numbers be 3x, 2x and 5x.
Then,
9x + 4x + 25x =1862
⇒ 38x = 1862
⇒ x = 49 ⇒ x = 7.
middle number = 2x = 14

Total students = 3200

Boys = 1800

Girls = 1400

Ratio of girls to boys = 1400 : 1800 = 7 : 9

Let Cherry = x.

Then Amit = (x-20) and Bittu = (x-40).

x + x - 20 + x - 40 = 120 Or x = 60.

Amit : Bittu : Cherry = 40 : 20 : 60 = 2 : 1 : 3

Bittu's share = Rs. 120x (1/6) = Rs. 20

Treat 3 : 9 as 3/9 and x : 9 as x/9, 

So we get

3/9 = x/9

⇒ 9x = 27

⇒ x = 3

A+B+C = 147

A : B = 2 : 3

B : C = 5 : 8

Since both ratios consider B, write A : B : C as one ratio around B’s LCM of 15.

A : B ⇒ 10 : 15

B : C ⇒ 15 : 24

A : B : C = 10 : 15 : 24

10+15+24 = 49 “parts”, but we know A+B+C = 147 so triple each value.

∴ A : B : C is actually 30 : 45 : 72

Hence, the answer is 45.

Given two numbers are in the ratio=12:26= 6: 13

Let the required number be 6x and 13x

The LCM of 6x and 13x is 78x

= 78x = 312

x = (312/78)

x = 4

Thus the numbers are 6x = 6 (4) = 24

13x = 13 (4) = 52

In this type of question, we will first try to calculate the ratio of two persons. Once we get ratio then we can easily get our answer. So lets solve this.

(8/30)A = (2/5)B

A : B = 3 : 2

B's Share = 2/5 × 1210 = 484

Given x : y = 3 : 5

We can write above equation as

x/y = 3/5

5x = 3y

x = 3y/5

By substituting the value of x in given equation 3x + 4y : 8x + 5y we get,

3x + 4y : 8x + 5y = 3 (3y/5) + 4y : 8 (3y/5) + 5y

= (9y+20y)/5 : (24y+25y)/5

= 29y/5 : 49y/5

= 29y : 49y

= 29 : 49

Let the number to be added is xin the ratio =21:39=7:13

Then, (7 + x) + (13 + x) = (2/3)

(7 + x) 3 = 2 (13 + x)

21 + 3x = 26 + 2x

3x – 2x = 26 – 21

x = 5

Hence the required number is 5