help me please.

Race Speed: At the World Championship races held at Rome's Olympic Stadium in 1987, American sprinter Carl Lewis ran the 100-m race in 9.86 sec. His speed in meters per second after + seconds is closely modeled by the function. f ( + ) = 11.65 (1 - e-+/ 1:23 ) a) How fast, to the nearest hundredth was he running as he crossed the finish line? 5) After how many seconds, to the nearest hundredth, was he running at the rate of 10 m pes sec