SOLUTION: a boy is five years older than his sister. if the sum of their ages is 31. how old is each now?

Question 83367: a boy is five years older than his sister. if the sum of their ages is 31. how old is each now?
Found 2 solutions by stanbon, Kalmetam:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
a boy is five years older than his sister. if the sum of their ages is 31. how old is each now?
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Let sister's age be "x" ; boy's age is "x+5".
EQUATION:
x + x+5 = 31
2x=26
x=13 yrs old
x+5 = 18 yrs old
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Cheers,
Stan H.
Answer by Kalmetam(43) (Show Source): You can put this solution on YOUR website!
Ok, for this, lets try a chart seeing which two numbers add up to 31 up until the Brother (first number)is older than the Sister (2nd number) and see which one has the boy 5 years older than his sister.
0-31
1-30
2-29
3-28
4-27
5-26
6-25
7-24
8-23
9-22
10-21
11-20
12-19
13-18
14-17
15-16
16-15
Look closely and you'll see that 18 is 5 higher than 13. This means the boy is 18 and his sister is 13

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