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 24 ' ' x 24 ' ' square metal plate needs to be fixed by a carpenter on to a wooden board. the carpenter uses nails all along the edges of the square such that there are 25 nails on each side of the square. each nail is at the same distance from the neighboring nails. how many nails does the carpenter use ?
Options: ['a. 94', 'b. 95', 'c. 96', 'd. 97', 'e. 98']
[A]: c


[Q]: Problem: solution y is 30 percent liquid x and 70 percent water. if 2 kilograms of water evaporate from 6 kilograms of solution y and 2 kilograms of solution y are added to the remaining 4 kilograms of liquid, what percent of this new solution is liquid x ?
Options: a. 33 %, b. 35 1 / 2 %, c. 37 %, d. 40 %, e. 42 %
[A]: d


[Q]: Problem: you have been given a physical balance and 7 weights of 40, 42, 36, 33, 47, 52 and 67 kgs. keeping weights on one pan and object on the other, what is the maximum you can weigh less than 169 kgs.
Options: a. 163, b. 166, c. 162, d. 164, e. 165
[A]:
e