Let the cost of renting a chair be x and for renting a table be y than 5x + 3y = 31 and 2x + 6y = 52 2x+ 6y = 52 can be further simplified to x + 3y = 26 now try solving for x and y... best of luck:D
Time for first plane = 625 / 250 = 2.5 hours after 1.25 hours boeing 747 takes 1.25 hours (2.5 - 1.25) to arrive at the same location at the same time so, speed = distance / time = 625 / 1.25 = 500 the average speed of the boeing 747 is 500 mph