Let x be the amount James had this morning
Then his sister had 2x and his brother had x + 27
After his sister pays James and his brother 12 dollars each, she has 2x - 24 dollars and his brother has x + 27 + 12 dollars......and his brother has twice as much as his sister....so we have.....
2(2x - 24) = x + 27 + 12 simplify
4x - 48 = x + 39 simplify
3x = 87 divide both sides by 3
x = 29 this is what James had before his sister pays him $12.....so he has $[29 + 12] = $41, now
Check :
James' sister starts with $2(29) = $58
And his brother starts with $[ 29 + 27 ]= $56
After the sister pays both brothers $12......
She has $[58 - 24 ] = $ 34 and James's brother has $[56 + 12 ] = $68 ...... and his brother has twice as much as his sister......!!!
