Answer: 18 double rooms; 9 single rooms
Explanation:
Double+Single rooms= 27 rented rooms
x+y=27
$34 per day X amount of double rooms, $26 per day Y amount of single rooms= $846
34x+26y=846
Express Y in X terms
34x+26(27-x)=846
34x+702-26x=846
8x=144
x=18
Plug the value of x=18 in the original equation
18+y=27
y=27-18
y=9