To produce an old photograph, a photographer charges x dollars to make a negative, 3x/5 dollars for each of the first 10 prints, and x/5 dollars for each print in excess of 10 prints. If 45 dollars is the total charge to make a negative and 20 prints from an old photograph, how many dollars the photographer charges to make a negative?

Correct Answer: 3
According to the question, x + 10 × (3x/5) + (20 - 10) × x/5 = 45 or, x + 6x + 2x = 45 or, 9x = 45 or, x = 45/9 = $5