How to convert 840 seconds to hours?
We know (by definition) that:
We can set up a proportion to solve for the number of hours.
Now, we cross multiply to solve for our unknown :
Conversion in the opposite direction
The inverse of the conversion factor is that 1 hour is equal to 4.28571428571429 times 840 seconds.
It can also be expressed as: 840 seconds is equal to hours.
An approximate numerical result would be: eight hundred and forty seconds is about zero point two three hours, or alternatively, a hour is about four point two nine 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.