On an algebra test ,the highest grade was 42 points higher than the lowest grade. the sum of the two grades was 138 find the lowest grade

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?

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

What numbers are included in the set of integers? what numbers are not included?