It was 19 kilometers from the campgrounds to the lake. joel and mario rode their bicycles from the campgrounds to the lake and back again. if the round trip took them 2 hours, what was their average speed in kilometers per hour?

answer: -8.2562234e+13

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)