How to convert a scientific notation into percent? ?

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

The larger of two number is 4 less than twice the smaller number. the sum is 41. find the numbers

Can someone me out here and the tell me the greatest common factor