Question

Ratio of present age of A&B is 4:5,while that of C&D is 6:7 if 10 years ago ratio of age of A&Cis 1:2andthat of B&D is 3:5 find average age of A,B,C,D together​

Answer 1

Answer:

A=4x

B=5x

C=6x

D=7x

A to Q

4x-10/6x-10=1/2

8x-20=6x-10

2x=-10+20

2x=10

x=5

so now A=4*5=20

B=5*5=25

C=6*5=30

D=7*5=35

Average of a, b, c, d=20+25+30+35/4=27.5

Answer 2

Answer:

Ages of A,B,C,D are 20,25,30,35 years respectively.

Step-by-step explanation:

Given,Ratio of present age of A and B is 4:5.

and ratio of present age of C and D is 6:7

10 year ago,

Ratio of ages of A and C is 1:2 and ratio of ages of B and D is 3:5.

Let present ages of A,B,C,D are 4x,5x,6x and 7x respectively.

Before 10 years,age of A was (4x-10) years

and age of C was (6x-10) years.

According to question,

$\frac{4x - 10}{6x - 10} = \frac{1}{2}$

By cross multiplication,

$8x - 20 = 6x - 10$

$8x - 6x = 20 - 10$

$2x = 10$

$x = 5$

So age of A is $(4 \times 5) = 20$years.

Age of B is $(5 \times 5) = 25$years.

Age of C is $(6 \times 5) = 30$years.

Age of D is $(7 \times 5) = 35$years.