What is the value of resistor R in the figure(Figure 1) if V=7V and I=6A?

What is the value of resistor R in the figure(Figure 1) if V=7V and I=6A?

Express your answer using two significant figures.

Answer:

1/10 + 1/15 + 1/R = 1/R(net)

according to Ohm’s Law: I*R(net) = V

=> R(net) + V/I => 7/6

=> 1/R(net) = 6/7 = 1/10 + 1/15 + 1/R

=> 6/7 – 1/10 – 1/15 = 1/R

=> 0.69047619047619047619047619047619 (used Windows Calculator)

=> R = 0.69047619047619047619047619047619 ^ -1

=> R = 1.4482758620

=> R = 1.44 ohms