## kaiteDID 3 years ago Use the three steps to solve the problem. Two years ago a father was four times as old as his son. Three years from now the father will be only three times as old as the son. How old is each now? {son is yrs., father is yrs.}

1. ajprincess

Let the present age of son be x and the age of father be y. Can u tell me what was the age of the father two yrs ago?

2. kaiteDID

no i dont know i am srry

3. ajprincess

Subtract 2 from the present age y.

4. kaiteDID

so it would be 2-y*4 right?

5. ajprincess

hmm no. The age of father two yrs ago is y-2. And the son,s is x-2. Since it is given that the father's age was 4 times the age of son y-2=4(x-2). Getting it?

6. kaiteDID

kinda

7. ajprincess

Is it confusing? If so plz ask.

8. kaiteDID

yes it's confusing

9. ajprincess

How old are u nw?

10. ajprincess

what was ur age before two yrs?

11. ajprincess

U subtracted to frm ur present age to find the age bfore 2 yrs. right?I assumed father's present age to be y. then his age before two yrs wud have been y-2. Is is it clear?

12. kaiteDID

yes

13. ajprincess

The age of the son bfore two yrs wud hav been x-2. Getting it?

14. kaiteDID

mmhhh

15. ajprincess

sorry? isn't t clear?

16. kaiteDID

it is

17. ajprincess

Since it is given that the age of the father was 4 times the son's age y-2=4(x-2)

18. ajprincess

Getting it?

19. kaiteDID

yes

20. ajprincess

What will be the age of the father after three years?

21. kaiteDID

y+3

22. ajprincess

yup right:)

23. ajprincess

What will be the age of the son?

24. kaiteDID

x+3

25. ajprincess

Since it is given that the father's age will be three times of the age of the son y+3=3(x+3) getting it?

26. kaiteDID

okay

27. ajprincess

So u hav two eqns y-2=4(x-2) y+3=3(x+3) Can u find x and y?

28. kaiteDID

y-2=4x-8 y+3=3x=9

29. ajprincess

y-2=4x-8 y+3=3x+9 ya right:). Nw solve these equations to find x and y. can u do it?

30. kaiteDID

idk

31. ajprincess

y-2=4x-8 what do u get when u add 2 to both sides?

32. kaiteDID

10

33. ajprincess

y-2+2=4x-8+2 y=4x-6

34. ajprincess

y+3=3x+9 What do u get when u subtract 3 from both of the sides?

35. kaiteDID

12

36. ajprincess

hmm no. y+3-3=3x+9-3 y=3x+6 Getting it?

37. kaiteDID

yes

38. ajprincess

So u have two eqns y=4x-6 y=3x+6. Since both 4x-6 and 3x+6 are equal to y you can equate them. 4x-6=3x+6 Can u find x nw?

39. kaiteDID

10

40. ajprincess

hmm no. 1.Add 6 both sides 2.Subtract 3x both sides. What do u get nw?

41. kaiteDID

1x

42. ajprincess

That is vat u get in left hand side. What do u get in ur right hand side?

43. kaiteDID

0

44. kaiteDID

@robtobey can u help me?

45. robtobey

Solve the following for f and s, the father's and son's current age respectively.$\left\{\frac{f-2}{s-2}=4,\frac{f+3}{s+3}\text{=}3\right\}$Can you solve the above for f and s?

46. kaiteDID

idk i dont know how to do it

47. robtobey

Is the following easier?$\{f-2=4(s-2),f+3=3(s+3)\}$

48. kaiteDID

i dont know this is all confusing to me

49. robtobey

focus on the equation on the left. f - 2 = 4 (s - 2) Multiply out the RHS f - 2 = 4 s - 8 Move -2 to the RHS. f = 4 s - 8 + 2 Add -8 and +2 f = 4 s -6 Replace f in the second equation with 4 s -6 f + 3 = 3 (s + 3) (4 s -6) + 3 = 3 (s + 3) Can you solve the above for s and get a number?

50. kaiteDID

son is 7

51. robtobey

I have to log off now. The answer is$\{f=42,s=12\}$ You should verify the answer yourself.

52. kaiteDID

okay