How to solve this dimensional analysis/stoichometry problem

This problem has been giving me a headache for the last hour on my homework. Does anyone have any pointers in the right direction?



> 
> Finally, on January 28th, 2014, in Germany, a barn containing 90 cows exploded when a stray spark caught the methane trapped in the building on fire. Assume that the 90 cows were producing 250 L of methane per day and that there was a 15 hour collection in the barn when it ignited. What mass of water was generated in the explosion?
> 
> 
> 


This problem is specifically about combustion, and I'm assuming I'd have to multiply the combustion equation for methane by 90 somehow. I'm also assuming I'd have to divide 250 / 15 to get the correct liters of methane produced at this time.




Figured it out, thanks to @M. Farooq's help.
I first did some cross multiplication of 250/24 times X/15 to find out that in 15 hours, there would be 156.25 L of methane. This is equal to 86.56 grams of methane. Using that, I found out there were 5.393 moles of methane, and multiplying that by 2 (because for every one methane it makes 2 waters) I found that there would be 10.79 mol of water when the reaction was done. This, times the molar mass of water, gives me 194.4 grams of water after the explosion.


 1