Math, asked by archanavkchauhan1985, 2 months ago

the difference between the age of a mother and her daughter is 24 years the sum of the reciprocal of their age is 1 by 9 complete the following activity to find mother age​

Answers

Answered by spondita24
5

Answer:

m-d= 24

m= 24+d-----1

1/m+1/d= 1/9

d+m/md= 1/9

9(d+m)= md

put 1 in this equation

9(d + 24 + d) = d(24+d)

9(2d + 24) = d x 24 + d x d

2d x 9 + 24 x 9 = 24d + d^2

18d + 216 = 24d + d^2

0= d^2 +24d - 18d -216

0 = d^2 + 6d -216

0 = d^2 +18d -12d -216

0 = d(d + 18) - 12(d + 18)

0 = (d-12)(d+18)

case 1

d +18 = 0

d= -18

rejected cause age is never negative

case 2

d-12 = 0

d= 12

Thus 12 is the correct value of d

if d is 12

then m = d + 24

= 12+24

= 36

Step-by-step explanation:

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Answered by shaswat8080
1

Given that

Difference between age of mother and her daughter is 24 year

Sum of reciprocal of their age is

 \frac{1}{9}

To find

Mother age

Solution

Let

x and y is the age of mother and her daughter then as per given condition

x - y = 24

Then as per second given condition

 \frac{1}{x}  +  \frac{1}{y}  =  \frac{1}{9}

By doing cross multiplication we get

 \frac{y + x}{xy}  =  \frac{1}{9}

By swaping left hand side and right hand side we get

9(y + x) = xy

From first given condition we can take

x = 24  + y

then we get

9(y + 24  + y) = (24 + y)y

by multiplication we get

 {y}^{2}  + 6y - 216 = 0

By factors of this equation we get

y =  - 18 \\ y = 12

We can not take negative value as age hence

y = 12

Hence

Age of daughter is 12year

and age of her mother is

x = 24 + 12 \\  = 36year

hence Age of mother is 36year.

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