Answer: 4000
Explanation:
Q=250 - .25P +4Pc, where Q is the quantity of DVR
We want to find the partial derivative of Q with respect to Pc
(dQ/dPc,partial) = 4
There is a change of 4 DVR added. Since the Q is measured in Thousands.
∆Q = 4000
Differentiation Q with respect to Pc gives other terms to be zero except wrt Pc.