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 at first?

Answer 1

Answer:

Step-by-step explanation:

Let d =  digital cameras

Let m =  manual cameras

 

d + m = 240   .....( 1)

 

(d-82) = 3(m-26)  

d - 82 = 3 m - 78

d - 3 m = 82 - 78

d - 3m = 16         ...(2)

 

 Subtaracting equation 1 from 2

d + m = 240

d - 3m = 16        

---------------

  -4m = -224

     m = -224/-4

     m = 56

 

d + m = 240

d = 240-m

d = 240-56

d = 184

 

He had started with 184 digital cameras and 56 manual cameras .

 

 

Answer 2

After the donation, 3m + m = 132 manual = 33 digital = 99 Before the donation, he had 82 more digital and 26 more manual cameras. 82 + 99 = 181 digital 26 + 33 = 59 manual For a double check, before donation, digital + manual = 240 181 + 59 = 240 So, to begin with, the number of digital cameras = 181.