You have in your possession numerous resistors with a value

You have in your possession numerous resistors with a value of 2.50 ohm each. What is the smallest number you could hook together to get an effective resistance of 1.380 ohm? (Enter the smallest possible whole number of resistors.) How would you connect them? in parallel in series

Solution

as Req is greater than R

=> we must add an resistor in series

as Req =(R1+R2+ .....) in series ( which is greater than R1 , R2)

=> 1.380 = n*2.50*10^-3

=> n = 552 no of resitors