The number of cellular phone customers of a particular telephone company increased by an average of 40%/a from 1994 to 1998. If there were 963 300 customers on January 2, 1998, then the number of customers on January 2, 1994, to the nearest hundred, would have been

Answer: 250800

t5=963300, n=5

tn=a*r^(n-1)

My question is how they determine ratio=1.4?? please somebody can give me an easy explanation!!