If the coefficient of correlation r = −.81,the standard deviations of x and y are 20 and 25,respectively,then cov(x,y)must be −405.0.

Mantago wants to borrow $10,000 to buy a used car.He examined his budget and decided that he can afford a payment of $200 a month.If his bank offers him an APR of 7.5%,how long should he borrow the money so he can afford his monthly payment?

A) 3.5 years
B) 4 years
C) 4.5 years
D) 5 years