Finding resistance and temp co-efficient

[neduet]

Homework Statement

A motor winding has a risitance of 80 ohm at room temperature of 20c before
switching on to a 230v. after 4 hour run wionfing resistance is 100 ohm
find the temperature rise if the matrial resistance temperature co-efficient is 1/234.5/c.

R at 20 = 80 ohm
R at t = 100 ohm
alpha =1/234.5

Homework Equations

R at 20/R at t = R at 0c (1 - at)/ R at 0c (1-at)

The Attempt at a Solution

80/100 = 1+0.004264X20/1+0.004264t

t = 83.630 c

Rise is t-20 = 83.630-20
t rise is 63.63 c

 

[Lok]

The rise does not take into acount the initial temperature as if it were in Kelvin it would have been 293.5. The actual result should be 83.63.

 

[neduet]

The rise does not take into acount the initial temperature as if it were in Kelvin it would have been 293.5. The actual result should be 83.63.

but solution is right? and answer 83.63 is ok with this statement