presalie

a cyclist travels at a distance of 10.0 km. in 30 min. after w/c he speeds up to 40 km/hr for 6.0 more mins. Find his average speed.

The star nearest to our solar system is said to be 3.8 ly away. How many km. away is this if a spaceship can travel at the speed 100 times that sound , how long armed it take that spaceship to travel from the earth to the nearest star. Express your answer...