Question

A parallel combination of three resistors takes a current of 7.5A from a 30V supply. If the two resistors are 10ohm and 12ohm, find the third one.

Answer 1

First calculate the effective resistance

R=R1R2R3/R1+R2+R3

R=200R3/30+R3

according to ohms law V=IR

30=7.5(200R3/30+R3)

30(30+R3)=7.5(200R3)

900+30R3=1500R3

R3=1.63ohm

Answer 2

hey your answer is 15 ohm.

i have uploaded two images since one of them is blur.