TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a passenger bus that is driving down the street'. Find frequency of the letter 'r'

SOLUTION: 3

PROBLEM: Sentence: 'a parking meter painted green with a sign that describes it as not a parking meter'. Find frequency of the letter 's'

SOLUTION: 4

PROBLEM: Sentence: 'a farmer's market table with bananas, mangos, starfuit and limes'. Find frequency of the letter 'a'

SOLUTION:
10