SOLUTION: My son is in Honors Algebra in the 8th grade. I'm trying to help him figure this problem out but can't seem to get it. Please help. If Alex gives Bobby $4, then Alex would hav

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Question 271128: My son is in Honors Algebra in the 8th grade. I'm trying to help him figure this problem out but can't seem to get it. Please help.
If Alex gives Bobby $4, then Alex would have half as much money as Bobby. If Bobby gives Chris $7, then Chris would have $35 more than Bobby. If Chris gives Alex $17, then Alex would have $1 more than Chris.
How many dollars does each person have?
Thanks for your assistance.
Sincerely,
Will Schultz

Answer by Theo(13342)   (Show Source): You can put this solution on YOUR website!
let a = amount of money alex has originally.
let b = amount of money bobby has originally.
let c = amount of money chris has originally.

If Alex give Bobby $4, then Alex would have half as much money as Bobby.

Equation we get is:

(a-4) = (b+4)/2

multiply both sides of these equations by 2 to get:

2a-8 = b+4

subtract 4 from both sides of this equations to get:

b = 2a-12

If Bobby gives Chris 7, then Chris would have $35 more than Bobby.

equation we get is:

(c+7) = (b-7) + 35

subtract 7 from both sides of this equation to get:

c = b-7+35-7 which becomes:

c = b + 21

If Chris gives Alex 17, then Alex would have 1 more than Chris.

Equation we get is:

a+17 = c-17 + 1

subtract 17 from both sides of this equation to get:

a = c-17+1-17 which becomes:

a = c-33

We have 3 equations to work with.

They are:

b = 2a-12 (first equation)
c = b + 21 (second equation)
a = c-33 (third equation)

substitute 2a-12 for b in the second equation to get:

c = (2a-12) + 21 which becomes:
c = 2a-12+21 which becomes:
c = 2a + 9

substitute 2a+9 for c in the third equation to get:
a = (2a+9)-33 which becomes:
a = 2a+9-33 which becomes:
a = 2a-24

subtract a from both sides of this equation and add 24 to both sides of this equation to get:

a = 24 ***********************************************************

substitute 24 for a in the first equation to get:

b = 2*24-12 which becomes:
b = 48-12 which becomes:
b = 36 ***********************************************************

substitute 36 for b in the second equation to get:

c = 36 + 21 which becomes:
c = 57 ***********************************************************

we get:
a = 24
b = 36
c = 57

Now to see if this is accurate.

Equation from the first transaction is:

(a-4) = (b+4)/2

substitute 24 for a and 36 for b to get:

24-4 = 36+4/2 which becomes:
20 = 40/2 which is true !!!!!

Equation from the second transaction is:

(c+7) = (b-7) + 35

substitute 57 for c and 36 for b to get:

57+7 = 36-7 + 35 which becomes:
64 = 29 + 35 which becomes:
64 = 64 which is true !!!!!

Equation from the third transaction is:

a+17 = c-17 + 1

substitute 24 for a and 57 for c to get:

24+17 = 57-17+1 which becomes:
41 = 41 which is true !!!!!

All equations are true so the answers must be good.

Answers are:

Alex has $24
Bobby has $36
Chris has $57









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