SOLUTION: Immeadiate help pls!! Answer all with solutions and explanations using one variable which is X only.Thanks! 1. Dave is four times as old as Rob. Five years ago, Rob was 30 yea

Question 931198: Immeadiate help pls!! Answer all with solutions and
explanations using one variable which is X only.Thanks!
1. Dave is four times as old as Rob. Five years ago, Rob
was 30 years younger than Dave. Find their present
ages.
2.Tom is 8 years older than Alex. 3 years ago, Alex was
2 years more than one-third as Tom was then.How old is tom.
3.John is twice as old as his wife Mary. Five years
ago,John was 10 years younger than 3 times Mary's
age. How old is Mary now?
Found 2 solutions by ewatrrr, stanbon:
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
1. x Rob's age
x-5 = (4x-5) - 30, x = 10, Rob's age. His father is 40. And... 5 = 35 - 30
......
2. x Alex's age
x - 3 = 1/3(x+8 - 3) + 2
3x-9 = x + 5 + 6
2x = 20
x = 10, Alex's age. Tom 18
and...
7 = 5 + 2
........
x Mary's age
2x - 5 = 3(x-5) - 10
2x - 5 = 3x - 15 - 10
20 = x, Mary's age. John 1s 40
And...
35 = 45 - 10
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
1. Dave is four times as old as Rob. Five years ago, Rob
was 30 years younger than Dave. Find their present
ages.
D = 4R
R = D-30
---
Substitute::
R = 4R-30
-3R = -30
Rob = 10 yrs
D = 4R = 40 yrs
-----------------------
2.Tom is 8 years older than Alex. 3 years ago, Alex was
2 years more than one-third as Tom was then.How old is tom.
T = A + 8
A-3 = (1/3)(T-3)+2
-----
Substitute::
T-8-3 = (1/3)T - 1 + 2
T-11 = (1/3)T + 1
(2/3)T = 2
T = 3 yrs
----------------
3.John is twice as old as his wife Mary. Five years
ago,John was 10 years younger than 3 times Mary's
age. How old is Mary now?
J = 2M
J-5 = 3(M-5)-10
2M-5 = 3M-25
M = 20 yrs
--------------
Cheers,
Stan H.
------------
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