john is 2 years younger than candy .15 years later their ages will be ratio 9:10

Question

I want to know present age of candy ?explain me so that I can slove same problems based on this method sir

Answer 1

C=Candy's age

C-2=John's age

in 15 years...

C+15=Candy's age

C-2+15=John's age

C+15=Candy's age

C+13=John's age

the ratio of their ages now is 9/10

C+13/C+15=9/10

cross multiply

10(C+13)=9(C+15)

10C+130=9C+135

10C-9C=135-130

C=5 years old for Candy

C-2=5-2=3 years old for John

Answer 2

Hi Habeeba,

 

If I were to tell you that John is 7 years old you would tell me that Candy is 9, right?

What if he is 11? You wouldn't have a problem knowing that Candy is 13. And so on.

 

How did you find out that Candy is 9 when I told you that John is 7?  You added 2!

 

Now if you start saying that John is "x" years old - and you don't even know what "x" is yet - how old should Candy be?

Answer - you just add 2 like you did before and say "x + 2"

 

If you would call Cindy's age "y" now you have "y" equaling "x + 2", that is your equation 1.

 

y = x + 2     eq(1)

 

If John is "x" years old now how old will he be 15 latter? x + 15, right?

 

What about Candy? if she is "y" years old now, how old will she be 15 years from now? y + 15, right?

 

At that 15 year the ratio of John's age to that of Candy is 9:11.

 

All this means is that if you were to divide John's age at that time with that of Candy (YOU DON'T CALCULATE YET. YOU JUST SET UP) you will get 9/11

=> (x+15)/(y + 15 = 9/11   //but you now know that y = x + 2

=> (x+15)/(x+2+15) = 9/11

 

I hope this helps