The painter should charge you $3,250 to paint that house.
Missing info:
A painter charges by the square foot and charges you $1,875 to paint a 750 square foot rental house.
y = kx
y = total payment to painter
x = number of square foot painted
k = unit price of 1 square foot painted
Given: y = 1875 ; x = 750 ; k = ?
k = y / x ⇒ k = 1875/750 ⇒ k = 2.50 per sq. ft
y = ? ; x = 1300 ; k = 2.5
y = kx
y = 2.5 * 1300
y = 3,250