Question

Emma took 35 pictures of flowers on a nature walk and an additional 3 pictures of each bird she saw. She took a total of 83 pictures. Which equation can be used to find the number of birds, x, that Emma saw on her walk?

Answer 1

83 = 3x + 35

The total number of pictures taken is 83, so the equation is equal to 83.
The word each indicates that the variable will be multiplied. Since Emma takes 3 pictures for each bird she saw, 3x will indicate the number of bird pictures taken. 
35 flower pictures have already been taken, so this value is added to the number of bird pictures Emma took.