How old is James now?

James’ dad is 5 times older than James, and James is twice as old as his sister Sara. In two years, the sum of their ages will be 58. How old is James now? 

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Ages now
x = James’ sister’s age now
2x = James’ age now {James is twice as old as his sister}
10x = James’ dad’s age now {James’s dad is 5 times older than James}

Ages in 2 years
x + 2 = James’ sister’s age in 2 years {added 2 onto sister’s current age}
2x + 2 = James’ age in 2 years {added 2 onto James’ current age}
10x + 2 = James’ dad’s age in 2 years {added 2 onto James’ dad’s current age}

x + 2 + 2x + 2 + 10x + 2 = 58 {in 2 years, the sum of their ages will be 58}
13x + 6 = 58 {combined like terms}
13x = 52 {subtracted 6 from each side}
x = 4 {divided each side by 13}
2x = 8 {substituted 4, in for x, into 2x}

James (represented by 2x) is 8 right now

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