SOLUTION: Kathy is seven years older than bill. Sally is five years younger than Kathy. The sum of their ages is 45. How old is each child?

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Question 1101301: Kathy is seven years older than bill. Sally is five years younger than Kathy. The sum of their ages is 45. How old is each child?
Found 3 solutions by jorel1380, ikleyn, josgarithmetic:
Answer by jorel1380(3719) About Me  (Show Source):
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Let b be Bill. Then Kathy is b+7, and Sally is b+7-5, or b+2. So:
b+b+7+b+2=45
3b=36
b=12
Bill is 12, Kathy is 19, and Sally is 14
☺☺☺☺

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
Kathy + Bill + Sally       = 45

K      + B    + S          = 45

(B+7)  + B     + ((B+7)-5) = 45

=================>


3B + 7 + 7 - 5 = 45


3B + 9 = 45  ====>  3B = 45 - 9 = 36  ====>  B= 36%2F3 = 12.


Answer.  Bill is 12 yeras old. Kathy is b+7 = 12+7 = 19 years,  Sally is K-5 = 19-5 = 14 years old.


Check.   12 + 19 + 14 = 45.   ! Correct !

Solved.



Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
k Kathy
b Bill
x Sally

system%28k=b%2B7%2Cx=k-5%2Ck%2Bb%2Bx=45%29

Make these substitutions in the age-sum equation: system%28b=k-7%2Cx=k-5%29

k%2B%28k-7%29%2B%28k-5%29=45------one equation in one unknown variable.
-
3k-12=45
3k=57
highlight%28k=19%29-----Kathy
highlight%28Bill=12%29
highlight%28Sally=14%29

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check:
19+12+14=30+9+6+6=30+15=45
ok