Question

{[(20+5)//10ohms]+5ohms}//10ohms

Answer 1

R = (25//10) + (5//10).
R = (25*10)/(25+10) + (5*10)/(5+10)
R = 250/35 + 50/15
R = 7.14 + 3.333 = 10.476 Ohms.