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 businessman earns $28800 in December, thus decreasing his average annual (January to December) earnings by $1300. His average annual earnings would be
Source: CMAT Preparation

Option A: $29000

Option B: $33500

Option C: $40200

Option D: $41000

Option E: $43100
Option E

Question: The average marks of a class of 35 students is 45 and that of another class of 55 students is 65. Find the average marks of all the students?

Option A: 52.6

Option B: 52.4

Option C: 52.1

Option D: 57

Option E: 52.9
Option D

Question: The ratio of speeds of a car, a train and a bus is 5:9:4. The average speed of the car, the bus and the train is 72 km/hr together. What is the average speed of the car and the train together ?

Option A: 84 km/hr

Option B: 74 km/hr

Option C: 34 km/hr

Option D: 64 km/hr

Option E: 14 km/hr
Option A