SOLUTION: Ann's age is seven-tenths of Bill's age. In 4 years Ann's age will be eight-elevenths of Bill's age. How old is Bill now? I am having a difficult time with setting up the equa

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Question 323329: Ann's age is seven-tenths of Bill's age. In 4 years Ann's age will be eight-elevenths of Bill's age. How old is Bill now?
I am having a difficult time with setting up the equation due to the fractions. Any and all help will be appreciated. Thank you.

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Let a = Ann's present age
Let b = Bill's present age
:
Write an equation for each statement:
:
"Ann's age is seven-tenths of Bill's age."
a = 7%2F10b
or
a = .7b
:
"In 4 years Ann's age will be eight-elevenths of Bill's age."
a + 4 = 8%2F11(b + 4)
Multiply both sides by 11
11(a+4) = 8(b + 4)
11a + 44 = 8b + 32
11a = 8b + 32 - 44
11a = 8b - 12
Replace a with .7b
11(.7b) = 8b -12
7.7b = 8b - 12
12 = 8b - 7.7b
12 = .3b
b = 12%2F.3
b = 40 is Bills age
;
:
Find a
a = .7(40)
a = 28 is Anns age
check solution in the statement:
"In 4 years Ann's age will be eight-elevenths of Bill's age."
28 + 4 = 8%2F11(40+4)
32 = 8%2F11*44
32 = 32