Bunuel
If it costs d dollars to make the first 100 copies of a poster and e dollars for each poster after that, what is the total cost of 125 posters?
A. 25d + 100e
B. 100d + 25e
C. 125de
D. d + 25e
E. 125/(de)
The trap lies in the phrasing. If the question says "d dollars," the dollars have already been included in the lone variable
d.
That is, "d" (dollars) has already been multiplied by 1 dollar. Don't multiply by dollars again.
(And don't multiply by 100
cents unless the problem mentions cents.)
If you see "
e dollars" think:
"___ dollars" = "
10 dollars" = $10.00 = e
When we say "10 dollars" we actually mean $10.00
Let the first 100 copies cost $100. d = $100
Let each extra copy = $2.00. e = $2
How much do 125 copies cost?
$100 for the 100 copies
($2 * 25) = $50 for the next 25
Total $150
If we use Answer B)
\(100d + 25e\) ...We get
\((100*$100)+(25*$2)=($10,000+$50)=$10,050\)Answer D)
\(d + 25e\)
\($100 + (25 * $2) = ($100 + $50) = $150\) That's correct
Answer D
As with d dollars, the p in "p percent" includes the percent. Percent means "per hundred." If I say 50 percent, I am really saying \(\frac{50}{100}\). If I decide "p percent" is 60 percent, I plug in p = 60, not p = .6. If I plug in p = .6, I get \(\frac{.6}{100} = .006,\) which is not even 1%.