Suppose a deli sells morning newspapers at an average of 10 per hour with a standard deviation of 5. use the standard normal distribution.

a. what is the probability that the deli will sell up to 7 newspapers in a given hour?
b. what is the probability that the deli will sell 12 or more newspapers in a given hour?

a) 0.274 is the probability that the deli will sell up to 7 newspapers in a given hour.

b) 0.345 is the  probability that the deli will sell 12 or more newspapers in a given hour.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 10 per hour

Standard Deviation, σ = 5 per hour

Formula:

a) P(deli will sell up to 7 newspapers in a given hour)

P(x < 7)

Calculation the value from standard normal z table, we have,  

0.274 is the probability that the deli will sell up to 7 newspapers in a given hour.

b) P( deli will sell 12 or more newspapers in a given hour)

P(x > 12)

Calculation the value from standard normal z table, we have,  

0.345 is the  probability that the deli will sell 12 or more newspapers in a given hour.

"standard form:

3x2 + 14x − 10 = 0

solutions based on quadratic formula:

x1   = −14 − √ 142 − 4×3×(−10) /   2×3   = −14 − 2 × √ 79 /   6   ≈ −5.296

x2   = −14 + √ 142 − 4×3×(−10) /   2×3   = −14 + 2 × √ 79 /   6   ≈ 0.629