What is the greatest common factor of 30,48,and 60

Which of the following is correct interpretation of the expression -4+13

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.

Need solving this 2nd limit problem.