10N means 0.010 inch. 15N means 0.015 inch. There are exactly 25.4mm in 1 inch. You therefore have to multiply by 25.4 in order to convert inches into millimeters. O.01 x 25.4 = 0.254 mm and 0.015 x 25.4 = 0.381 mm. The correct answer is that your required range is 0.254 - 0.381 mm.
