Correct Option: AExplanation:
Solution
Let the required number of days be x
more students,less days(indirect proportional)
more pencils,more days(direct proportional)
students 15:5::9:x
pencils 18:66::9:x
(15×18×x)=(5×66×9)
x=5×66×9/15×18
x=11
Hence the required number of days is 11