A poster 30 inches wide and 60 inches long is to be mounted in a frame of uniform​ width, x. Why is the combined width of the poster and frame expressed as ​30+2x ?

Question

A.) Because the width is 30 feet more than twice its length

B.) Because the combined width is 30 feet longer than the poster length

C.) Because the same frame width is added to the length and width of the poster

D.) Because two frame widths are added to the poster width.

Answer 1

A) is wrong W=2L+30 would mean 30=120+30 = 150 which isn't true

B) is wrong. 30+2x is not 30 more than 60

C)is wrong. frame width = x, 30+x and 60+x is not the dimensions of the framed poster, it's 30+2x by 60+2x

D is correct. the frame width is on both sides of the poster width, so 30+2x is poster + 2 frame widths