Two unknown resistors are connected together. When they are connected in series their equivalent resistance is 15 Ω. When they are connected in parallel, their equivalent resistance is 3.3 Ω. What are the resistances of these resistors?

Explanation:

Let x and y are two unknown resistors. When they are connected in series their equivalent resistance is 15 Ω. When they are connected in parallel, their equivalent resistance is 3.3 Ω.

For series combination,

......(1)

For parallel combination,

....(2)

We need to find the resistances of these resistors. Solving equation (1) and (2) we get :

x = 0.29 and y = 14.7

Hence, the resistances of these resistors are 0.29 ohms and 14.7 ohms.