Question

calculate resistance from a to b (correct only)​

Answer 1

first calculate series combination from last i.e 10ohm and 15 ohm

$r = 10 + 15 = 25$

R=25ohm

now calculate next combination

means 25ohm and 30 ohm they are in parallel

$\frac{1}{r} = \frac{15 + 30 }{15 \times 30} = \frac{45}{15 \times 30} = \frac{3}{30} = \frac{1}{10 } \\ r = 10$

so now our resistance is 10 ohm now again we calculate .

$\frac{15 + 20 + 10}{35 \times 10} \\ \\ \frac{35 + 10}{35 \times 10} \\ \\ \frac{45}{35 \times 10} \\ \\ \frac{9}{7 \times 10}$

$\frac{1}{r} = \frac{9}{70}$

so R =70/9

resistance from a to b is ⤵️

$\frac{70}{9}ohm$