Question

SO how many mins. are in 900 s

Answer 1

I think it is 15 hrs, if you take 60x15=900 and then take 60 div 900= 15 hrs. You might want to make sure from someone else but that is what I really do think. Good Luck

Answer 2

900 s x (1 min/60 s) = ??
You know there are 60 seconds in 1 min so the factor is EITHER 60 s/1 min OR
1 min/60 s. Which do we use? Use the one in which the unit we don't want cancels and leaves the unit we want for the answer. Note that in my first line, seconds in the numerator cancels the seconds in the denominator (we want to get rid of seconds) and it leaves min as the only unit (and the want the answer in minutes). So we know to use 1 min/60 sec.
Try it if you wish with 60 s/1 min and see that it gives you
900 s x (60 s/1 min) = 54,000 and the unit is seconds squared/min. That isn't the unit we want for the answer so we KNOW this isn't the factor to use.