# 8.99*10^9 seconds is how many years?

Sep 7, 2016

$\text{285 years}$

#### Explanation:

Your strategy here will be to use a series of conversion factors to take you from

• seconds to minutes

$\text{1 minute " = " 60s seconds}$

• minutes to hours

$\text{1 hour " = " 60 minutes}$

• hours to days

$\text{1 day " = " 24 hours}$

• days to years

$\text{1 year " = " 365.25 days}$

The last conversion factor doesn't use a whole number because once every $4$ years we have what is called a leap year, which means that instead of $365$ days, the number of days we have in a regular year, we get $366$ days.

So, use the conversion factors to find

8.99 * 10^9 color(red)(cancel(color(black)("s"))) * (1color(red)(cancel(color(black)("min"))))/(60color(red)(cancel(color(black)("s")))) * (1color(red)(cancel(color(black)("hr"))))/(60color(red)(cancel(color(black)("min")))) * (1 color(red)(cancel(color(black)("day"))))/(24color(red)(cancel(color(black)("hr")))) * "1 year"/(365.25color(red)(cancel(color(black)("days"))))

$= 2.85 \cdot {10}^{2} \text{years" = "285 years}$

The answer is rounded to three sig figs, the number of sig figs you have for $8.99 \cdot {10}^{9}$ seconds.