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: A and B complete a work in 6 days. A alone can do it in 10 days. If both together can do the work in how many days?

 Option A: 3.75

 Option B: 3.76

 Option C: 3.79

 Option D: 3.74

 Option E: 3.71
Option A

Question: A train sets off at 2 p.m. at the speed of 70 kmph. Another train starts at 3:30 p.m. in the same direction at the rate of 85 kmph. At what time the trains will meet?

 Option A: 10.36

 Option B: 10.39

 Option C: 10.3

 Option D: 10.34

 Option E: 10.31
Option C

Question: Two cyclist start on a circular track from a given point but in opposite direction with speeds of 7m/s and 8m/s. If the circumference of the circle is 630meters, after what time will they meet at the starting point?

 Option A: 20sec

 Option B: 15sec

 Option C: 42sec

 Option D: 50sec

 Option E: 1min

Option C