Answer:
R = 11.8 ohms
Explanation:
Formula
R = R_ref[1 + a(T - T_ref)]
Givens
Solution
R = 10*[1 + 0.004(65 - 20)]
R = 10*[1 + 0.004(45)]
R = 10*[1 + 0.18]
R = 10*(1.18)
R = 11.8 ohms
Be sure you understand not to add the 1 and 0.004 together. You don't get 1.004 at any point of the solution. If you do, you won't know what to do (exactly) with the 45.