Divide four people into three rooms, in which only one room could host two people. How many ways are there to arrange them so that A, B are not in the same room

Option 1: $30 an hour plus a nonrefundable deposit of $50 option 2: $20 an hour plus a nonrefundable deposit of $75 kyle is renting a jetski for the day. if he can rent the jetski in one hour increments, what is the minimum number of hours must he rent the jetski for option 2 to be a better deal then option 1?

If i have a 24 in loaf of bread and i cut it into two pieces one 9 in how long was the other

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.