Hi there, I got 156.7 m/s for Part A, but the answer for Part B is 163% of the speed of sound or mach 2. However, I'm not sure how that is the result. When I divide 156.7 by 343, I get .456, which is not 163%. A little guidance would be helpful! Thank you.

On February 15, 2013, a superbolide meteor (brighter than the Sun) entered Earth's atmosphere over Chelyabinsk, Russia, and exploded at an altitude of 23.5 km. Eyewitnesses could feel the intense heat from the fireball, and the blast wave from the explosion blew out windows in buildings. The blast wave took approximately 2 minutes 30 seconds to reach ground level. (a) What was the average velocity of the blast wave? b) Compare this with the speed of sound, which is 343 m/s at sea level