SOLUTION: Five yrs hence, the ages of ram and his son will be in the ratio of 5:2. Three yrs ago, the ratio of their ages was 7:2. find the present age of his son.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Five yrs hence, the ages of ram and his son will be in the ratio of 5:2. Three yrs ago, the ratio of their ages was 7:2. find the present age of his son.      Log On


   

Question 866294: Five yrs hence, the ages of ram and his son will be in the ratio of 5:2. Three yrs ago, the ratio of their ages was 7:2. find the present age of his son.
Answer by mananth(16946) About Me  (Show Source):
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ram ---x years
son y years
5 years hence
x+5 / y+5 = 5/2
2(x+5)=5(y+5)
2x+10 = 5y+25
2x-5y=15................(1)
x-3 /y-3 = 7/2
2(x-3)=7(y-3)
2x-6=7y-21
2x-7y=-15.................(2)

2 x -5 y = 15 .............1
2 x -7 y = -15 .............2
Eliminate y
multiply (1)by -7
Multiply (2) by 5
-14 x 35 y = -105
10 x -35 y = -75
Add the two equations
-4 x = -180
/ -4
x = 45
plug value of x in (1)
2 x -5 y = 15
90 -5 y = 15
-5 y = 15 -90
-5 y = -75
y = 15
Ram 45 years , son 15 years