This is a situation of direct variation.

Because, less number of basket balls —–> cost will be less.
Given :
75 basketballs cost = $1,143.75.
Cost of one basket ball = 1143.75 / 75 = 15.25
Then, cost of 26 basket balls = 15.25 x 26 = 396.50.
Hence, the cost of 26 basket balls is $ 396.50.