Calculate the net effect that a change in the annually compounded risk-free rate from 6.83 percent to

Question:

Calculate the net effect that a change in the annually compounded risk-free rate from 6.83 percent to 6.60 percent would make on the price of a commodity futures contract whose spot price as of March 30 was $49.90, assuming that there is a $5.60 storage cost and the futures contract expires on November 30?