Answer
$ a. 220±20k= [180, 260], k = (220-180)\div20 = 2 $
$Minimum \ percentage = 1-\frac{1}{2^2} = 3/4*100 = 75%$
$b. 220±20k = [160, 280], k = (220-160)\div20 = 3$
$Minimum \ percentage = 1-\frac{1}{3^2} = 8/9*100 = 88.89%$
$c. 220±20k = [170, 270], k = (220-170)\div20 = 2.5$
$Minimum \ percentage = 1-\frac{1}{2.5^2} = 0.84*100 = 84%$
Work Step by Step
$ a. 220±20k= [180, 260], k = (220-180)\div20 = 2 $
$Minimum \ percentage = 1-\frac{1}{2^2} = 3/4*100 = 75%$
$b. 220±20k = [160, 280], k = (220-160)\div20 = 3$
$Minimum \ percentage = 1-\frac{1}{3^2} = 8/9*100 = 88.89%$
$c. 220±20k = [170, 270], k = (220-170)\div20 = 2.5$
$Minimum \ percentage = 1-\frac{1}{2.5^2} = 0.84*100 = 84%$
