A family made a down payment of $75 and borrowed the balance on a set of encyclopedias that cost $400. The balance with interest was paid in 23 monthly payments of $16 each and a final payment of $9.
The amount of interest paid was what percent of the amount borrowed ？（）

单项选择题A car traveled 462 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city. If the car traveled 6 fewer miles per gallon in the city than on the highway, how many miles per gallon did the car travel in the city ？（）

A．14
B．16
C．21
D．22
E．27

单项选择题All of the tickets for two real estate seminars, F and G, were either purchased or given away, and the ratio of F tickets to G tickets was 2 to 1. Of the total number of F tickets and G tickets, what percentage was purchased ？（） (1)The total number of F tickets and G tickets is 240. (2)Of the F tickets, exactly 60 percent were purchased, and of the G tickets, exactly 80 percent were purchased.

A．条件(1)充分，但条件(2)不充分．
B．条件(2)充分，但条件(1)不充分．
C．条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
D．条件(1)充分，条件(2)也充分．
E．条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．