Straightforward, this reads "7 is 5% of how many?". Algebraically, the word "is" means an equals sign, and the word "of" means you multiply. Of course, the 5% needs to be in decimal form. Taking the sentence above, algebraically it is: 7 = .05x. Divide by .05 on both sides to get x = 140
For finding values related to a normal probability distribution function, it is convenient to use a suitable calculator or spreadsheet. (See below)
If all you have is a z-table, you must calculate the corresponding z-value and look it up in the table.
z = (X -µ)/σ = (56 -54)/8 = 1/4
You are interested in the area above z=1/4. The table in the second attachment gives the area between z=0 and z=1/4. So, the area of interest is the table value subtracted from 0.5 (the total area above z=0.):
To evaluate this you just have to create an equation to solve this problem, it says that Julian has $15 in total, and he has to buy at least one notebook, so you´d have to withdraw the money of a notebook from the total, and the pens cost 4.50 each, we will be expressing the number of pens by "X" and the number of notebooks by "y" so your equation would be like this:
The number of notebooks is one, so you can put it into the equation:
Now you clear "x"
Since he can not buy .55 of a pen, he will only be able to buy 2 pens.