help with physics (response time) 3 MULTIPLE CHOICE?

1.) Aarons normal response time to apply car brakes is .7 seconds. Arron's response time doubles when he is tired. how far will aarons car travelduring the time it takes him to apply the brakes when his car is moving at 30 meters per second when he is tired?

A) 84 meters

B) 42 m

C) 92 m

or

D) 21 m

2.) A group of bike riders took a 4 hour trip. During the first 3 hours, they traveled 50 kilometers, but during the last hour they traveled only 10 kilometers. What was the groups average speel for the entire trip?

A) 30 km

B) 15 km

C) 40 km

D) 60 km

3.) A runner starts from rest and accelerates uniformly to a speed of 8 meters per second in 4 seconds. What is the magnitude of runners acceleration?

A) 50 m/s squared

B) 9.8 m/s squared

C) 2 m/s squared

D) 32 m/s squared