How to convert 840 seconds to weeks?
We know (by definition) that:
We can set up a proportion to solve for the number of weeks.
Now, we cross multiply to solve for our unknown :
Conversion in the opposite direction
The inverse of the conversion factor is that 1 week is equal to 720 times 840 seconds.
It can also be expressed as: 840 seconds is equal to weeks.
An approximate numerical result would be: eight hundred and forty seconds is about zero weeks, or alternatively, a week is about seven hundred and twenty times eight hundred and forty seconds.
 The precision is 15 significant digits (fourteen digits to the right of the decimal point).Results may contain small errors due to the use of floating point arithmetic.