Help Please - Simultaneous Equations - Worded Problems

[chuckjefster90]

Hey Guys,
Would you be able to help me with these two simultaneous equations.
Could you also define the variables?
I've put the answers at the bottom.
Thank you so much.

1) Mr Magoo is 7 time as old as his daughter Lulu. In 5 years, he will be 4 times as old as Lulu will be then. Wht are their present ages?

2) Find 2 numbers such that if 18 is added to the first number it becomes twice the second number and if 6 is added to the second number it becomes three times the first number.

Answers
1) 5 and 35                2) 6 and 12

[nbalakers24]

let mr magoo = x
let lulu = y

x= 7y
5+x= 4y

solve. i think thats the two equations :S

[charliemei123]

Let Mr Magoo's age now be x and Lulu's age now be y

so x=7y and x+5=4(y+5)

so sub x=7y into other equation

7y+5=4y+20

3y=15

y=5, hence x=7y=7(5)=35

So Mr Magoo is 35 now and Lulu is 5 now :S

[m@tty]

Let Mr Magoo's present age = m
Let Lulu's present age = l

Equation 1

In 5 years Lulu's age will be l+5
and Mr Magoo's age will be m+5

Equation 2 .

So . Equation 2'

Let equation 2' equal equation 1 () and solve.

[Cthulhu]

"Find 2 numbers such that if 18 is added to the first number it becomes twice the second number and if 6 is added to the second number it becomes three times the first number. "
Let x be the first number and y the second number.
(1)
(2)
From Equation 2:






Plugging this into equation 1:

[m@tty]

2.

let the first number be x and the second be y.

(1)

and

(2)

Multiply the second equation by 2.

  (2)'

Take equation (1) away from equation two prime, (2)':









Sub into first equation:





.

[chuckjefster90]

thanks guys