Answer:
450 minutes
Explanation:
Since Elijah can build 5 model airplanes in 150 minutes. He can build 1 model airplane in 30 minutes. To find this you divide 150 by 5. The question asks for how many minutes it would take Elijah to build 15 model airplanes. Since 1 x 15 = 15 model airplanes, you use proportions and also multiple the time by 15, so 30 x 15 = 450 minutes.