SOLUTION: In 2 years a boy will be three-fourths as old as his sister. Two years ago he was two-thirds as old as she. How old are they?? ?

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Question 908979: In 2 years a boy will be three-fourths as old as his sister. Two years ago he was two-thirds as old as she. How old are they?? ?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
b+ 2 = (3/4)(s+2)
b = (3/4)s + (3/2) - 2 = %283%2F4%29s+-+1%2F2
b -2 = (2/3)(s-2)
%283%2F4%29s+-+1%2F2 - 2 = (2/3)s - 4/3
%289%2F12%29s+-+%288%2F12%29s+=+-4%2F3+%2B+1%2F2+%2B+2 |Multiplying thru by 12 so as all denominators = 1
9s - 8s = -16 + 6 + 24
s = 14, sister's age NOW, boy is 10. b%2B+2+=+%283%2F4%2916using 1st EQ to find b