150/75 = 2 hours
150/60 = 2.5 hours
150/50 = 3 hours
150/20 = 7.5 hours
If a random sample of 20 persons weighed 3,460, the sample mean x-bar would be 3460/20 = 173 pounds.
The z-score for 173 pounds is given by:

Referring to a standard normal distribution table, and using z = 0.66, we find:

Therefore

The answer is: 0.2546
The better buy would be four bunches for $10.66 because each bunch of flowers would be $2.66 compared to $3.16 per bunch.