Lenny Conumdrum 3/21/07

1392 maybe...let me double check

EDIT: double checked and here's the work

Code (Text):

1. x-y = 12
2. xy=17
3.  
4. find y in terms of x
5. xy=17
6. y=17/x
7.  
8. substitute into the first equation
9. x-(17/x) = 12
10.  
11. multiply each side by x to get rid of fractions
12. x^2 + 17 = 12x
13. x^2 - 12x + 17 = 0
14.  
15. put into quad form
16. x = 6 (+ or -) 53^(1/2)
17. x is probably not negative to use 6 + 53^(1/2)
18.  
19. substitute back into first equation
20. (6 + 53^(1/2)) - y = 12
21. y = -6 + 53^(1/2)
22.  
23. solve
24. (6 + 53^(1/2)) * 100 + (-6 + 53^(1/2)) * 50 = 1392
25.  
26.  

 

lol, 3 threads in the same minute!

 

what are the original two numbers

 

how did you work it SoC?

 

6 + 53^(1/2) and -6 + 53^(1/2)

awww...and I did all that work by hand :cry:

 

i used my friends brain

 

actually, no. if you round, its 1393

13.29 * 1.279253518 = 17.00127....

soo...original numbers are: 13.29 and 1.279253518

13.29 * 100 = 1329

50(1.279253518) + 1329 = 1392.962676

rounded = 1393

+rep appreciated

 

I got 931?

Ok, so:

X-Y=12

XY=17

Solve the second equation for Y and you get:

Y= (17/X)

Substitute the new Y value into the new equation and X - (17/X) = 12

Multiply everything by X to get rid of it in the denominator and:

X^2 -17=12

X^2=29

X=5.3851

Since X-Y=12

Y=6.6148

100 x 6.6148 = 661.48
50 x 5.3851 = 269.25

661.48 + 268.25 = 930.73

Rounded, 931.

But I seem to have gotten a different answer than some people?

 

read my post above xD

 

actually it's 1.280109889281 and 13.280109889281

same with me

 

So close! Oh well Nice job to everyone else for finding better methods than by hand.

 

but then why would they want you to round?

 

round at the very end...never before

EDIT: lol...SoC answered first

 

you can see thats wrong, cuz Y - X isnt 12