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.

Q: Problem: a bag contains 10 green and 8 white balls. if two balls are drawn simultaneously, the probability that both are of the same colour is
Options: a. 8 / 15, b. 21 / 44, c. 3 / 5, d. 11 / 15, e. 7 / 15

A: b
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Q: Problem: the dimensions of a room are 10 m x 7 m x 5 m. there are 2 doors and 3 windows in the room. the dimensions of the doors are 1 m x 3 m. one window is of size 2 m x 1.5 m and the other 2 windows are of size 1 m x 1.5 m. the cost of painting the walls at rs. 3 per sq m is
Options: a. 2488, b. 378, c. 739, d. 474, e. 291

A: d
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Q: Problem: the sum of the numbers is 550. if the first number be twice the second and third number be one - third of the first, then the second number is :
Options: a. 48, b. 150, c. 72, d. 84, e. 27

A:
b
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