Answer
P = 0.05 (5%) means that the reading speed will be $93.9\approx 94$ wpm
Work Step by Step
For P = 0.95, z = 1.645. Here n = 20, hence:
$σ_{x̄} = σ / \sqrt n = 10/\sqrt 20 = 2.24$
$z = \frac{x̄ - μ_{x̄}}{σ_{x̄}}$
$x̄ = μ_{x̄} + z.σ_{x̄} $
$= 90 + 1.645 (2.24)$
= $93.9\approx 94$ words per minute
