-0.6+3/4 x (-1 3/5)=​

-51/20

Explanation:

solve -13/5 first

then multiply it by the 3/4

then add -0.6

Resistance is proportional to length and inversely proportional to area.

L1 =  5 cm

L2 = 10 cm

L3 = 15 cm

A1 = k * (.50 cm)^2

A2 = k * (.25 cm)^2 = 1/4 A1

A3 = k * (.05 cm)^2= 1/100 A1

R1 = 1 * 1 = 1

R2 = 2 * 4 = 8 R1

R3 = 3 * 100 = 300 R1

R3 has greatest resistance