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Mr. Perez is 3 times as old as his daughter now. In 15 years’ time, the sum of their ages will be 86 years. Find their ages now.

 Feb 14, 2020
 #1
avatar+27 
+3

Let's use the reverse process. Assume p is Mr.Perez's age and d is his daughter's age. Because there are two people's ages combined, we multiply 15 by 2, =30. 86-30 = 56.The ratio p:d is 3:1, 3+1 = 4, and 56/4 = 14. 14*3 gives us 42. 

 

To check, 42/3 = 14, 42+14+15+15=56+30=86.

 

Mr.Perez is 42 now, and his daughter is14  now. If you  have any questions, don't hesitate to ask. :)

 
 Feb 14, 2020
edited by hugomimihu  Feb 14, 2020
 #2
avatar
+2

Let the daughter's age now =D
Her dad's age now                 =3D

 

D +15 + 3D + 15 =86, solve for D
D = 14 years - daughter's age now
14 x 3 = 42 years - her dad's age now.

 
 Feb 14, 2020
 #4
avatar+27 
+2

Oh yes, sorry, I misread the problem. It is indeed 14 and 42, let me change that! Thanks!

 
hugomimihu  Feb 14, 2020
 #3
avatar+107011 
+1

Let his daughter's age now  = A

And the father's age now = 3A

 

In 15 years   ....his daughter's age = A + 15

And the father's age at that time will be   3A + 15

 

So

 

(A + 15)  + (3A + 15)  =  86    simplify

 

4A + 30  = 86     subtract  30 from both sides

 

4A  = 56   divide both sides by 4

 

A = 14 =  his daughter's age now

3A  = 3*14 = 42  = her father's age now

 

 

cool cool cool

 
 Feb 14, 2020
 #5
avatar+27 
+1

I like your thinking for using only one variable- smart! I should do that sometime... You know, from what I know, the probability of me getting the same answer as you is higher than the chances of Melody having the same answer as you... Hmm...

 
hugomimihu  Feb 14, 2020
 #6
avatar+107011 
0

Thanks, hugo    !!!!

 

I knew what you meant by your first answer

 

[ I like to use one variable whenever possible  ..... ]

 

 

cool cool cool

 
CPhill  Feb 14, 2020

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