Answer:
7 Ω
Step-by-step explanation:
Given:
R1 = 21 Ω
The connection is parallel
Since all 3 of the resistors have the same resistance, we can use this formula to find the total resistance of the circuit:
R = R1/n (R1 is the resistance of one resistor and n is the number of resistors)
R = 21/3 = 7 Ω