SOLUTION: The sum of the ages for Peter and Paul is 24. Five years ago their respective ages were in the ratio 3:4. How old will they be in three years time?

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Question 1170973: The sum of the ages for Peter and Paul is 24. Five years ago their respective ages were in the ratio 3:4. How old will they be in three years time?
Found 3 solutions by math_tutor2020, MathTherapy, josgarithmetic:
Answer by math_tutor2020(3816) About Me  (Show Source):
You can put this solution on YOUR website!

E = peter's age right now
A = paul's age right now
Ages are in years.
I went with the second letter of their names since both started with P. Feel free to label your variables however you want.

"The sum of their ages is 24" means E+A = 24. We can solve for E to get E = 24-A.

Five years ago, their ages were E-5 and A-5
The ratio of these past ages was 3:4, which means we can say,
(peter's age 5 years ago)/(paul's age 5 years ago) = 3/4
(E-5)/(A-5) = 3/4
4(E-5) = 3(A-5) .... cross multiply
4E-20 = 3A-15
4(24-A)-20 = 3A-15 ... plug in E = 24-A
96-4A-20 = 3A-15
76-4A = 3A-15
76+15 = 3A+4A
91 = 7A
7A = 91
A = 91/7
A = 13

Paul is currently 13 years old. In three years time, he will be 13+3 = 16 years old.

E = 24-A
E = 24-13
E = 11

Peter is currently 11 years old. In three years time, he will be 11+3 = 14 years old.


Answers:
Peter will be 14 years of age
Paul will be 16 years of age

Answer by MathTherapy(10551) About Me  (Show Source):
You can put this solution on YOUR website!

The sum of the ages for Peter and Paul is 24. Five years ago their respective ages were in the ratio 3:4. How old will they be in three years time?
Let Peter's age be P
Then Paul's is: 24 - P
We then get:
4(P - 5) = 3(19 - P) ------ Cross-multiplying
4P - 20 = 57 - 3P
4P + 3P = 57 + 20
7P = 77
Peter or
Paul's age: highlight_green%28matrix%281%2C3%2C+24+-+11%2C+%22=%22%2C+13%29%29
Can you now find their ages, 3 years from now?

Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
r, peteR
L, pauL
system%28r%2BL=24%2C%28r-5%29%2F%28L-5%29=3%2F4%29
-
L=24-r
-
%28r-5%29%2F%2824-r-5%29=3%2F4
%28r-5%29%2F%2819-r%29=3%2F4
4r-20=3%2A19-3r
7r=77
r=11
-
L=13
-
-
In three more years:
system%28highlight%28r=14%29%2Chighlight%28L=16%29%29