Answer:
(4) 50 ohms (5) 11.76 ohms
Step-by-step explanation:
In the parallel combination, the equivalent resistance is given by :

4. When three 150 ohms resistors are connected in parallel, the equivalent is given by :

5. Three resistors of 20 ohms, 40 ohms and 100 ohms are connected in parallel, So,

Hence, this is the required solution.