R circuit (pretty simple) need checked - full working - please

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R circuit (pretty simple) need checked - full working - please!

Homework Statement



see attachment

Homework Equations


P=IV
P_loss=I^2 R
V=IR


The Attempt at a Solution


ok
36=I^2*12

I_12Ω=√3 A
V=20.8V
That is the same for the 3 resistors in parallel (I hope)
so I18Ω=1.15A
I36Ω=0.577A
the sum of these will give me the current through the unknown resistor
Iunknown=3.46A
net voltage = 60
60=Vunknown + 20.8
Vunknown=39.2V
V=IR
R=11.3Ω

can someone please check this - wouldn't ask if I dint need it.
 

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  • resistors.png
    resistors.png
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Sorry, I forgot the second half of the question,

P_loss=I^2 R
P=〖3.46〗^2*((1/12+1/18+1/36)^(-1)+11.3)
P_loss=207.6W
This seems big to me, could you please check that too.
 


pat666 said:
Sorry, I forgot the second half of the question,

P_loss=I^2 R
P=〖3.46〗^2*((1/12+1/18+1/36)^(-1)+11.3)
P_loss=207.6W
This seems big to me, could you please check that too.

your answer is correct.