Question

Mr. Rifkin had 240 digital and manual cameras. After donating 82 digital cameras and 26 manual cameras, he had 3 times as many digital cameras as manual cameras left. How many digital cameras did he have first?

Answer 1

He started with 184 digital cameras and 56 manual cameras

Work--> d + m = 240   equation 1 (d-82) = 3(m-26)  equation 2d - 82 = 3m - 78d - 3m = 82 - 78d - 3m = 16         equation 2 simplified  d + m = 240d - 3m = 16         subtract equation 1 from equation 2---------------   -4m = -224      m = -224/-4      m = 56 d + m = 240d = 240-md = 240-56d = 184