Answer:
$5.76
Step-by-step explanation:
Total price for 3.75 pounds of pears:
Total price for 2.10 pounds of pears:
Total Price:
Answer: (x – 1)(x + 1)(x + 5) = 0
x – 1 = 0, so x = 1
x + 1 = 0, so x = -1
x + 5 = 0, so x = -5
Let x be the number of days.
Daily pass:
65x + 30x
95x
Season pass:
400 + 30x
95x > 400 + 30x
65x > 400
x > 6.15
The number of days can't be 6.15, so you must round. You can't go down because then the price will be more expensive, so you have to round up.
It would take 7 days until the season pass is less expensive than the daily pass.
----------------------
You can check this by plugging in the x.
95x > 400 + 30x
95(7) > 400 + 30(7)
665 > 400 + 210
665 > 600
The daily pass is more expensive than the season pass.
We are choosing 2
2
r
shoes. How many ways are there to avoid a pair? The pairs represented in our sample can be chosen in (2)
(
n
2
r
)
ways. From each chosen pair, we can choose the left shoe or the right shoe. There are 22
2
2
r
ways to do this. So of the (22)
(
2
n
2
r
)
equally likely ways to choose 2
2
r
shoes, (2)22
(
n
2
r
)
2
2
r
are "favourable."
Another way: A perhaps more natural way to attack the problem is to imagine choosing the shoes one at a time. The probability that the second shoe chosen does not match the first is 2−22−1
2
n
−
2
2
n
−
1
. Given that this has happened, the probability the next shoe does not match either of the first two is 2−42−2
2
n
−
4
2
n
−
2
. Given that there is no match so far, the probability the next shoe does not match any of the first three is 2−62−3
2
n
−
6
2
n
−
3
. Continue. We get a product, which looks a little nicer if we start it with the term 22
2
n
2
n
. So an answer is
22⋅2−22−1⋅2−42−2⋅2−62−3⋯2−4+22−2+1.
2
n
2
n
⋅
2
n
−
2
2
n
−
1
⋅
2
n
−
4
2
n
−
2
⋅
2
n
−
6
2
n
−
3
⋯
2
n
−
4
r
+
2
2
n
−
2
r
+
1
.
This can be expressed more compactly in various ways.
