Simple Algebra Problem
I have a simple algebra problem that has been bugging me :)
"....the product of two numbers is 30. Their average is 6. What are the two number?"
I know this problem is easy; but, I cant seem to work it out.
I pretty much started out like this :
(a) let's say the numbers are X and Y
(b) so, average is 6. Meaning : (x+y) / 2 = 6
(c) Hence, x+y = 12
(d) Product : x * y = 30
(e) So : (x+y=12) and (x*y=30)
(f) Next, I decided to equate both expressions :
10(x+y) = 120
4(x*y) = 120
(g) So : 10(x+y) = 4xy
And, this is where I got stumped
Equating them wasn't much use since you didn't eliminate any of the numbers...
What you could do is:
x + y = 12
xy = 30
x = 12 - y
Substitute in the other equation;
y(12 - y) = 30
Can you finish it? :)
Now, I feel SOOOOOOOOOOO stupid :) :)