Jika R1=R2=5OHM dan R3=R4=4OHM hitumglah hambatan penggantinya?? Tolong dong?

Seri
Rs =R1+R2+R3+R4
=5+5+4+4
=18 ohm

paralel
1/Rp=1/R1+1/R2+1/R3+1/R4
=1/5+1/5+1/4+1/4
=4/20+4/20+5/20+5/20
=18/20
Rp =20/18
=1,11 ohm