This is a great instructional video on how to calculate the age of Universe from Hubble's constant. The speed the galaxy moves away from us is directly proportional to the distance from us. Now think of big bang theory. Hubble's constant is equal to velocity over distance. 1 over Hubble's constant is equal to distance over velocity that is equal to time. Time equals to 1over 71. If you change it into all the same units words it is one over 71000 or 3.09x 10 to the power of 22. It is 3.09x10 to the power 22 over 71000 seconds. It is 3.09x10 to the power 22 over 71000 and 31,556,926 years. The age of Universe is 13.8 billion years.