Count the number of strings of length 9 over the alphabet {a, b, c} subject to each of the following restrictions.

(a)

The first or the last character is a.

(b)

The string contains at least 8 consecutive a's.

(c)

The string contains at least 8 consecutive identical characters.

(d)

The first character is the same as the last character, or the last character is a, or the first character is a.

(e)

The string contains at least seven consecutive a's.

(f)

The characters in the string "abababa" appear consecutively somewhere in the 9-character string. (So "ccabababa" would be such a 9-character string, but "cababcaba" would not.)

(g)

The string has exactly 2 a's or exactly 3 b's.

(h)

The string has exactly 2 a's or exactly 2 b's or exactly 2 c's

The solution and complete explanation for the above question and mentioned conditions is given below in the attached document. I hope my explanation will help you in understanding this particular question.

Step-by-step explanation:

answer: city needs 2.4 inches of rainfall more to match the record of 40 inches.

step-by-step explanation:

since we have given that

total annual rainfall a city record = 40 inches

this year, total rainfall recorded = 37.6 inches

number of inches of rainfall   is needed to match the record of 40 inches is given by

hence, city needs 2.4 inches of rainfall more to match the record of 40 inches.

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right