A parallel combination of 3 resistances takes a current of 7.5 A from a 30 V supply. If two resistances are `10Omega` and `12 Omega`, find the third resistances.

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

A parallel combination of three resistors takes a current of 5A from a 20V supply. If the two resistors are of 10 ohm and 8 ohm, find the value of third resistor.