Let's make the LEAST number 'x' .....Then according to the question, the GREATEST number is ' 2x ' and the MIDDLE number is 'x + 3' Further the three numbers add up to 75 so:
x + (x + 3) + 2x = 75
2x + 3 + 2x = 75 Simplify:
4x + 3 = 75 Subtract 3 from each side of the equation
4x = 72 Divide both sides of the equation by 4
x = 18 is the least number the MIDDLE number 'x + 3' then equals 21 and the GREATEST number, 2x = 36