Question

sum of present ages of manish and savita is 31 manish age 3 yearsago was 4 times the age of savita find present age

Answer 1

Let the present age of Savitha be x years and the present age of Manish be y years.
Given that
Sum of their present ages is 31
Therefore
x + y = 31 (equation 1)

Also given 3 years ago, Manish's age is 4 times the age of Savitha.
Age of Manish 3 years ago = y - 3 years
Age of Savitha 3 years ago = x - 3 years.
Therefore
y - 3 = 4 (x - 3)
y - 3 = 4x - 12
4x - y = 9 (equation 2)

Adding equation 1 and 2
x + y = 31
4x - y = 9

5x = 40
x  = 8 years

x + y = 31
y = 31 - 8 = 23 years

The present age of Manish = 23 years
The present age of Savitha = 8 years.

Hope this helps you.

Answer 2

hye

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let svaita be s and manish be m

=>Sum of present ages of manish and savita is 31

=>s+m = 31

=>m = 31 - s...........[1]

=>manish age 3 years ago was 4 times the age of savita

=> 4[s-3] = m-3................[2]

=>now lets substitue [1] in [2]

since 4[s-3] = m-3 and  m = 31 - s................

=> 4[s-3] = 31-s -3

=>4s -12 = 28 - s

=>4s +s = 28+12

=>5s = 40

=>s = 8 

since m =  31-s = 31-8

=> 23 years 

maish is 23 and savita is 8

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hope it helps u...............