100 / 2 = 50 people in the theater have brown eyes. 100 / 4 = 25 people in the theater have black eyes. There are 50 + 25 + 19 = 94 people in the theater with either brown, black, or blue eyes. There are 100 - 94 = 6 people in the theater with green eyes.
The answer: 6
Reverse engineering the question: There are 100 people in a theater. If 19 of these people have blue eyes, half of them have brown eyes, a quarter have black eyes, and the rest have green eyes, how many of them have green eyes?

If there are half as many VW Bugs as there are Toyota trucks in this parking lot, and there are 5 VW Bugs, then there are 2 * 5 = 10 Toyota trucks in the parking lot. And if there are twice as many Ford trucks as Toyota trucks in this parking lot, then there are 2 * 10 = 20 Ford trucks in the parking lot. And if there are one - third as many Ford trucks as Dodge trucks in the parking lot, then there are 20 * 3 = 60 Dodge trucks in the parking lot of the Taco Castle.
The answer: 60
Reverse engineering the question: There are one-third as many Ford trucks as Dodge trucks in the parking lot of the Taco Castle. But there are twice as many Ford trucks as Toyota trucks in this parking lot, and there are half as many Volkswagen Bugs as there are Toyota trucks in this same parking lot. If there are 5 Volkswagon Bugs in the parking lot, how many Dodge trucks are in the parking lot of the Taco Castle?

If on Sunday 40 more people were present at the park than on Saturday, there were 200 + 40 = 240 people on Sunday. The total number of people at the park over the two days is 240 + 200 = 440.
The answer: 440
Reverse engineering the question: A park had 200 visitors last Saturday and 40 more visitors on Sunday than on Saturday. Calculate the total number of people in the park over the two days.

For the 30 - day pass to be cheaper, then the average fare should be cheaper than the $2 one - way ticket. If the 30 - day pass costs $50, then I should take at least $50 / $2 = 25 rides to pay the same as a one - way ticket. However, given that we want the 30 - day pass per ride to be strictly cheaper we should ride at least 25 + 1 = 26 times.
The answer: 26
Reverse engineering the question:
A one-way ticket costs $2. A 30-day pass costs $50. What's the minimum number of rides you will need to take every month so that the 30-day pass is strictly cheaper per ride?