Consider the following definitions for sets of characters: Digits = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 } Letters = { a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z } Special characters = { *, &, $, # } Compute the number of passwords that satisfy the given constraints.
a. Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters.
b. Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters. The first character can not be a special character.

a) Number of passwords: 2763633600

b) Number of passwords: 2487270240

Step-by-step explanation:

We have:

10 digits,

26 letters, and

4 special characters.

We have to compute the number of passwords that satisfy the following conditions:

a) Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters.

We can use the three types of characters, as long as they do not repeat.

We have a total of 10+26+4=40 characters.

This means we have 40 options for the first place, (40 - 1) for the second place (as the first place already use one of the options available), and so on up to 6 places.

We can write this as:

b. Strings of length 6. Characters can be special characters, digits, or letters, with no repeated characters. The first character can not be a special character.

In this case we add a restriction: the first character can not be a special character.

Then, for the first place we have only 40-4=36 options (digits and letters).

For the second place we can use the 39 options available (digits, letters and special characters).

Then we have:

the answer is a. q=6,r=6√2

step-by-step explanation:

third choice down

step-by-step explanation:

the first inequality is based on the number of adults and campers, and the second inequality is based on the cost of feeding both the adult and the camper.

we know that there is room for 525 people max.   it's ok to have less than 525, but it's not ok to have more than 525, so the inequality is less than or equal to.   the number combination of adults (x) and campers (y) cannot exceed this 525 max.   therefore:

x + y ≤ 525

now we talk about cost.   it costs $9 to feed one adult, so depending upon the number of adults you have (x) depends upon how much it will cost to feed that number of adults.   same with the campers, who cost $5 to feed.   the adults can be represented by 9x and the campers can be represented by 5y.   since the budget cannot exceed 1,200, the second inequality is:

9x + 5y ≤ 1200