The answer would be 45 weeks, since you do 530-80 since that is the part the parents will foot, which will be 450 left. Then you do that divided by 10 since you plan to save 10 dollars a week and therefore are left with 45 weeks.
Answer:
9 Model As.
Step-by-step explanation:
Let A represent Press A and let B represent Press B.
So, they own 14 total presses. This means that:

They can print 905 books per day, in other words, since A prints 70 per day and B prints 55 per day:

This is now a system of equations. Solve by substitution. From the first equation, subtract B from both sides:

Substitute this into the second equation: "

First, we can divide everything by 5 to simplify things:

Distribute the left:

Combine like terms:

Subtract 196 from both sides:

Divide both sides by -3

So, the company has 5 Model B presses.
Which means that the company has 14-5 or 9 Model A presses.
And we're done!
Let get all the information.
Mean:394
Deviation:35
Looking for At Least 380 feet
To find the z score you take the wanted probality subtract the mean and divide by the deviation.
z=(380-394)/35.
z=-0.4
So far so good.
But when he looked at the table he looked at probability that the home runs are less then 380 feet.
From this table
http://www.stat.ufl.edu/~athienit/Tables/Ztable.pdf
To find the answer you have to take 1-(the probability that the home runs are less than 380 feet)or 1-0.3446=0.6554
He made an error in his calculation.