Question:three 15 ohm resistors are connected in parallel to a 30 volt battery. what is the equivalent resistance through the circuit?

Three 15 ohm resistors are connected in parallel,  to a 30 volt , the current flowing , the current flowing through  a parallel circuit is not uniform, therefore for each resistor , the current flow through it is

V=ir, i=v/r

 i₁=v/r₁= 30/15 =2 amps

I₂=v/r₂ = 30/15 =2 amps

I₃=v/r₃ = 30/15 =2 amps

The total current that pass through the circuit is 2+2+2 = 6amps.

Checking:

The effective resistance through the circuit is 1/r_eff=1/r₁+1/r₂+1/r₃

1/r_eff=1/15 +1/15+ 1/15 =3/15=1/5

Therefore r_eff=5 amps

 current = v/ r_eff= 30/5 = 6amps