Question 619549
Sally,Sarah, and sue worked all summer to save money for school clothes.
Sarah(a) saved $50 more than twice as much as Sally(b) 
Sue(c) saved $100 more than 1/2 as much as Sally.
The total amount saved by the three girls was $1550. 
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How much did each girl save? 
Equations:
a  +  b  +  c  = 1550
a = 2b + 50
c = (1/2)b + 100
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Substitute for "a" and "c" and solve for "b":
(2b+50) + b + (1/2)b + 100 = 1550
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(7/2)b + 150 = 1550
(7/2)b = 1400
b = (2/7)*1400
b = $400  (Sally's share)
a = 2b+50 = $850 (Sarah's share)
c = (1/2)b+100 = $300 (Sue's share)
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Cheers,
Stan H.
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