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.

Question: The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:

 Option A: 70 km/hr

 Option B: 75 km/hr

 Option C: 84 km/hr

 Option D: 87.5 km/hr

 Option E: 88.5 km/hr
Option D

Question: How many inches are in 2000 millimeters? (round your answer to the nearest hundredth of of an inch).

 Option A: 51.45 inches

 Option B: 86.09 inches

 Option C: 67.34 inches

 Option D: 34.98 inches

 Option E: 78.74 inches
Option E

Question: How many digits are required to number a book containing 260 pages?

 Option A: 784

 Option B: 672

 Option C: 492

 Option D: 372

 Option E: 300

Option B