R1=40 ohm.R2=60 ohm.E=10 volt.r=1 ohm.besarnya kuat arus total dalam rangkaian tetsebut adalah

1/Rp = 1/R1 + 1/R2
1/Rp = 1/40 + 1/60
1/Rp = 3+2/120
1/Rp = 5/120
Rp = 120/5 = 24 Ohm

V = I x R
V = I x (R + r)
10 = I x (24+1)Ohm
10 = I x 25Ohm
I = 10/25
I = 0,4