eon is 1 billion yrs (1x10^9)how long is this in min Assume 1 year=365.25 days
You do this by using dimensional factors so the unit you don't want cancels and the unit you want to convert to stays. For example,
1 x 10^9 yrs x (365.25 days/yr). Note this converts years to days. The yrs in the numerator cancel the yr in the denominator and days is what we have left. Now you continue, knowing, there are 24 hours in a day, and 60 min in an hour. You should be left with minutes and all of the other units disappear.