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.

[EX Q]: Question: A library has an average of 1000 visitors on Sundays and 700 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is :

 Option A: 740

 Option B: 750

 Option C: 760

 Option D: 770

 Option E: 775
[EX A]: Option B

[EX Q]: Question: Working alone at its constant rate, machine K took 3 hours to produce 1/5 of the units produced last Friday. Then machine M started working and the two machines, working simultaneously at their respective constant rates, took 6 hours to produce the rest of the units produced last Friday. How many hours would it have taken machine M, working alone at its constant rate, to produce all of the units produced last Friday?

 Option A: 10

 Option B: 12

 Option C: 15

 Option D: 25

 Option E: 30
[EX A]: Option C

[EX Q]: Question: An engineer undertakes a project to build a road 10 km long in 150 days and employs 30 men for the purpose. After 50 days, he finds only 2 km of the road has been completed. Find the (approximate) number of extra men he must employ to finish the work in time.

 Option A: 22

 Option B: 30

 Option C: 15

 Option D: 18

 Option E: 20
[EX A]:
Option B