SOLUTION: 1/R(total)= 1/12 + 1/15 + 1/5 R(total)=? How is this solved? Thank you

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Question 200527: 1/R(total)= 1/12 + 1/15 + 1/5
R(total)=?
How is this solved?
Thank you
Answer by jim_thompson5910(21667) About Me  (Show Source):
You can put this solution on YOUR website!
1%2F%28R%5Bt%5D%29=1%2F12%2B1%2F15%2B1%2F5 Start with the given equation.


60%2Across%28R%5Bt%5D%29%281%2Fcross%28R%5Bt%5D%29%29=cross%2860%29%5E5%2AR%5Bt%5D%281%2Fcross%2812%29%29%2Bcross%2860%29%5E4%2AR%5Bt%5D%281%2Fcross%2815%29%29%2Bcross%2860%29%5E12%2AR%5Bt%5D%281%2Fcross%285%29%29 Multiply EVERY term by the LCD 60R%5Bt%5D to clear out the fractions.


60=5R%5Bt%5D%2B4R%5Bt%5D%2B12R%5Bt%5D Multiply and simplify


60=21R%5Bt%5D Combine like terms.


60%2F21=R%5Bt%5D Divide both sides by 21 to isolate R%5Bt%5D.


R%5Bt%5D=60%2F21 Rearrange the equation.


R%5Bt%5D=20%2F7 Reduce


R%5Bt%5D=2.8571 Approximate the right side


So the total resistance is approximately 2.8571 ohms (assuming that's the unit you're working with).


If you have any questions, email me at jim_thompson5910@hotmail.com.
Check out my website if you are interested in tutoring.