ElectricPavlov

Thanx GA....missed the 1/2 as long part  !!!!!  

I apologize !!!!!

the voltage increased 5 times   and the resistance is cut in half    so the current will increase   5 x 2 times

10 x 200 = 2000 mamps   

D'Oh !  

rate * time = distance

distance to and from is the same

r * 6.4   = 2d        or      r * 3.2 = d

d/(r-50) + d /(r+50) = 6.667         (I changed the minutes to hours)

3.2r /(r-50)  + 3.2r (r+50) = 6.667

3.2r (r+50) + 3.2r ( r-50) = 6.667 ( r+50)(r-50)

3.2 r^2  + 160r   + 3.2r^2  - 160r  =  6.667 r^2 -16667.5

-.2667 r^2 + 16667.5 = 0                   quadratic formula shows x = 250 m/hr

250 m/hr x 6.4 hrs = roundtrip distance = 1600 miles       800 miles one way

20 t * 36 m / 4800 ft^2 = .15 t m /ft^2

.15 t m / ft^2    *  3600 ft^2  / 9 t   =  60 min

It is not incorrect      1 amp = 1000 milliamps  ,   silly !

https://web2.0calc.com/questions/math-questi0n#r1

If you put 250 volts ACROSS the wire (you don't put voltage THROUGH a wire) the curent woud increase through the wire

250/50=  by 5 times       5 x 200 ma = 1 amp 

EDIT:::::  

BUT   you cut the wire in half....this cuts the resistance in HALF

    cutting the resistance in half will DOUBLE the current through the wire

          1 amp x 2 = 2 amps   = 2000 millimps

Gather like terms

9x^3 - 5x^3      + 2x^2      - 5x - -7x      + 4 -4

4x^3                + 2x^2      + 2x    

2x (x^2 + 2x + 1)

2x ( x+1)(x+1)

6 j  + 2 t = 20

3 j  + 5 t = 23       Multiply this equation by  -2

-6 j -10 t = -46     add to top equation

      - 8t = - 26

          t = 3.25                  6 j + 2 (3.25) = 20        j = $ 2.25

5 l + 6 s = 187

3 l + 2 s = 87           multiply this equation by -3

-9 l - 6 s = -261       add top and bottom equations

-4 l = -74

l = 18.5 kg           3(18.5) + 2s = 87      s = 15.75 kg