can anyone explain this question?

Question

If r1=2 r2=3 and r3=4
1/Rt=1/2+ 1/3+1/4
1/Rt=13/12
Rt=12/13
=.92
can anyone explain to me how they 13/12
step by step it’s a parallel circuit question

Answer 1

1/2 + 1/3 + 1/4 =
6/12 + 4/12 + 3/12 = 13/12
is that what you needed?

Answer 2

To solve half + one-third + a quarter, (1/2 +1/3 + 1/4) you have to find the lowest common multiple, which is the lowest number that can be divided by 2, 3, 4, (the denominators) without leaving a remainder. That number is 12. Convert the fractions using 12 as the denominator. 1/2 becomes 6/12, 1/3 becomes 4/12 and 1/4 becomes 3/12. (These are equivalent fractions) Add them up and you will get 13/12. You invert 1/Rt to get Rt/1 which is the same as Rt. Whatever you do to one side of the equation, do to the other side as well. Invert 13/12. You will get 12/13. Rt=0.92.
Hope I helped.

Answer 3

The formula for this question is 1/Rtotal=1/R1+1/R2+1/R3. If you substitute in all of your values, you get 1/2+1/3+/1/4. Once you add all of those values either by hand or with a calculator you get 1.083333 or 13/12 (common denominator is 12, 6/12+4/12+3/12). Then after putting the value under 1, you get the answer .923361034. The answer .92 is recieved by rounding to the hundreth's value. I hope that helps!

Answer 4

13/12 is the sum of 1/2 + 1/3 + 1/4.
To add up fractions, you convert them all to the least common denominator. In this case, 12 is the smallest number that is divisible by 2, 3, and 4. So how do you convert 1/2 to 12ths?
Multiply by 6/6 (which is the same as multiplying by 1), and you get 6/12. Similarly, you can convert 1/3 by multiplying by 4/4 to get 4/12. Finally, 1/4 * 3/3 = 3/12.
You now have 6/12 + 4/12 + 3/12. Now that the denominators are all the same, you can just add the numerators. 6 + 4 + 3 = 13, so the result is 13/12.

Answer 5

My understanding of your question is, you have 3 registers.

R1 is 2 ohms
R2 is 3 ohms
R3 is 4 ohms

You want to figure out what happens to the total resistance when you add all 3 in parallel.

If this is your question....

The whole formula is based not on resistance but conductance. Where as resistance is expressed in OHM, conductance is expressed in MHO (pronounced "mow") and the value is recipical of the ohm. It basically means how "easily" it will conduct electricity, where as resistance is how much difficulty it will pose to the current to pass through. Makes sense it is recipical, correct?

So... for each of the resisters,

R1 = 1/2
R2 = 1/3
R3 = 1/4

When you parallel them, you add them together first.

1/2 + 1/3 + 1/4
= 6/12 + 4/12 + 3/12
= 13/12

13/12 is the conductance of the resisters connected in parallel. Since you want RESISTANCE, not conductance, you take recipical of this value.

1/(13/12) = 12/13
= 0.92

If you want the simple formula, here it is....

Rt = 1 / ( (1/R1) + (1/R2) + (1/R3) + ....)

Good luck studying...!

Answer 6

because when adding the fractions in the second step, you need to convert the denominators to the least common denominator....which is 12, once you do that , you add all the top numbers...... and you get 13/12................what you do to the bottom, you must do to the top.....remember that

so... 1/2 = 6/12.........1/3 = 4/12...... 1/4=3/12
now add them up
6/12 + 4/12 + 3/12 = 13/12

Answer 7

1/2=6/12
1/3=4/12
1/4=3/12

13/12 is the sum of them and now you need to invert to find the equivalent total resistance

Answer 8

all the r display resisitance if i am not wrong here is expanation r1 stands for resistance 1 and r2 stands for resitance you add their reciprocal i will repeat reciprocal in finding the total resistance in the whole circuit. what they did is simply add the values reciprocal after finding 13/12 they simply cross mutliplied it
and please rate my question

Answer 9

eeegaaa! my brain hurts.

dont ask about my new word. its an inside joke. ha. ha. ha. XP