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.
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Question: Problem: cost is expressed by the formula tb ^ 4. if b is doubled, the new cost w is what percent of the original cost ?
Options: a. w = 200, b. w = 600, c. w = 800, d. w = 1600, e. w = 50

Answer: d

Question: Problem: a textile manufacturing firm employees 100 looms. it makes fabrics for a branded company. the aggregate sales value of the output of the 100 looms is rs 5, 00,000 and the monthly manufacturing expenses is rs 1, 50,000. assume that each loom contributes equally to the sales and manufacturing expenses are evenly spread over the number of looms. monthly establishment charges are rs 75000. if one loom breaks down and remains idle for one month, the decrease in profit is :
Options: a. 13000, b. 7000, c. 10000, d. 3500, e. none of these

Answer: d

Question: Problem: a 300 m long train crosses a platform in 48 sec while it crosses a signal pole in 18 sec. what is the length of the platform ?
Options: a. 500, b. 350, c. 828, d. 277, e. 122

Answer:
a