TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a yellow and green train on a train track in a wooded area'. Find frequency of the letter 'o'

SOLUTION: 4

PROBLEM: Sentence: 'young girl playing with refrigerator magnet while kneeling on floor'. Find frequency of the letter 'n'

SOLUTION: 6

PROBLEM: Sentence: 'the lunch set up includes a variety of foods'. Find frequency of the letter 'd'

SOLUTION:
2