must convert room dimientions to inches 25*12=300in 23*12=276in 15*12=180in Vroom=300*276*180=14904000in^3
now 1 billion bills
move decimal place over 9 places to right 1 million bills takes about 68909220 in^2
how many rooms to fit them all? vbillionbills/v1room=number of rooms needed= 68909220/14904000=4.623 round to 1 deicmal 4.6 rooms needed (actually, it would be 5 since you can't use the 0.4 room left over very efficiently)