Which of the following systems of inequalities has point D as a solution

Find the sum to the equation 3+6+9+

Cindy uses 1-inch cubes to find the volume of a jewelry box shaped like a rectangular prism. she uses 780 cubes to completely fill the jewelry box with no gaps or overlaps. if the jewelry box is 13 inches long and 5 inches wide, how tall is cindy’s jewelry box?

Mr and mrs smith buy tickets for themselves and their four children. the cost of an adult ticket is ? 6 more than the adult ticket. the total cost of the six tickets is ? 40.50 work out the cost of an adult ticket. in your working let c be the cost of the child ticket and a be the cost of the adult ticket.