at roberto’s construction site, the crew can frame a wall in 35 minutes and frame the opening for a door in 21 minutes. the crew needs 9 loads of materials for each wall and 13 loads of materials for each door. one day the crew worked for 595 minutes. and used 267 loads of materials. which system of equations could be used to find the number of doors. d. and walls. w, they framed?
a 35w + 9w = 595 35d + 13d = 267
b 21w + 35d = 595 9w+ 13d= 267
c 35w + 21d = 595 13w+ 9d = 267
d 35w + 21d = 595 9w+ 13d= 267