PHP Taskbook Level 2.10

Задание 1

Given a string of letters and numbers, check that there are no more than three letters in this string.

Задание 2

Given a number, get the first even digit from the end of this number.

Задание 3

Given a string:

php'abcde abcde abcde'

Replace the first character of each word in it with '!':

php'!bcde !bcde !bcde'

Задание 4

Given an array of numbers:

php[1, 2, 3, 3, 4, 5]

Check that this array contains two identical elements in a row.