Question

The sum of a brother's and sister's ages is 57 years.If the brother is 5 years older than his sister,find their ages.

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Answer 1

Answer: Brother = 31, sister = 26

Step-by-step explanation:

first, take 57, and minus the difference of the ages (5) = 52. divide that between both of them, getting 26, and 26. Since the brother is 5 years older, add 5 to one of the 26's and you get 26, and 31.

Check if its correct: 26+31=57

Answer 2

We can make formulas for this.

Assume x=male age and y=female age.

From this problem, we know that x+y=57 and x-5=y since the brother is older. We can do substitution and plug in the second formula into the first.

x+(x-5)=57

2x-5=57 Add like terms (x)

2x=62 Isolate

x=31

Then plug this into the original to find out y.

x+y=57

31+y=57

y=26