You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
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Question: Question: There is one highland where planes get fuel. A plan can cover the half of the world with full tank. A plane can transfer fuel from one plane to the other in the air. How many planes are required to make one plane cover the entire world once. Starting point of the travel is the Highland and coming back to the same Highland. All the other planes giving fuels to this Plane should also come back to the same highland and they don't have to cover the entire world.

 Option A: 2

 Option B: 3

 Option C: 4

 Option D: 5

 Option E: 6

Answer: Option D


Question: Question: A bag is filled with pennies and nickels in the ratio of 5 to 3. There are 30 nickles in the bag, how many coins are there in that bag?

 Option A: 70

 Option B: 65

 Option C: 75

 Option D: 85

 Option E: 80

Answer: Option E


Question: Question: The sequence a1, a2, a3, a4. a5 is such that an = a n-1 +5 for 2≤ n ≤ 5. If a5 = 33 what is the value of a1 ?

 Option A: 1

 Option B: 6

 Option C: 13

 Option D: 16

 Option E: 21

Answer:
Option C