Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
--------
Question: Problem: a person ' s present age is two - fifth of the age of his mother. after 8 years, he will be one - half of the age of his mother. how old is the mother at present
Options: a. 38, b. 40, c. 42, d. 44, e. 45

Answer: b


Question: Problem: if julie rows 32 km upstream and 72 km down steam taking 4 hours each, then the speed of the stream
Options: a. 1.5 kmph, b. 0.5 kmph, c. 0.4 kmph, d. 1.6 kmph, e. 2.5 kmph

Answer: b


Question: Problem: sarah operated her lemonade stand monday through friday over a two week period and made a total profit of 210 dollars. on hot days she sold cups of lemonade for a price that was 25 percent higher than the regular days. each cup she sold had a total cost of 75 cents and sarah did not incur any other costs. if every day she sold exactly 32 cups and 3 of the days were hot, then what was the price of 1 cup on a hot day ?
Options: a. $ 1.50, b. $ 1.64, c. $ 2.25, d. $ 2.50, e. $ 3.25

Answer:
b