The question is easily solvable while doing hardly any math at all. If the first half of the trip was completed at 50 mph and the second half of the trip were completed at 50 mph or less, then the average would never exceed 50 mph. Thus, choices C, D, and E can be eliminated. Choices A and B are so ...

A scalar solution path is the most direct method of solving this problem.

Since $0.66 is the tax for $12, the tax for $20 must be 20/12 of $0.66, a fraction that reduces to 10/6.

$0.66 * 10/6 = 0.11 * 10 = $1.10, which is answer choice (B).

This is a dubious critical reasoning question whose supposed best answer is (D). The first problem with this question is that there is no conclusion in the stimulus. Rather, what we find is a list of facts. The question stem asks us to evaluate "the result." However, it is unclear what thi...

You said: "Due to a malfunction, the mixing machine..."

But I hardly think a mixing machine can be due to a malfunction.

Since the trains are traveling towards each other, their speeds can be combined to 90 mph. Accordingly, the trains will meet at 300/90 hours, which reduces to 10/3 or 3 1/3 hours. Since Train A is going at 50 mph, it will have traveled more than 166.7 miles by the time the trains meet. Accordingly (...

Imagine that we are going to choose the chairman first. We have 10 different people we can choose from. Then we will choose the editor. Assuming that the same person cannot hold both positions (the problem doesn't say) that means that we will only have 9 people to choose from. Similarly, when we cho...

It's best to start with Data Sufficiency problems by asking yourself at the outset: What do I need? Well, regardless of whether x is even or odd, the first two terms of the equation will end up being either both odd or both even. Accordingly, everything will come down to whether the third term is od...

Just assign a number for x because it doesn't matter. I chose 10 meters, as it was a convenient number. Since Dan covered the 10 meters he was behind and got ahead by 10 meters in 20 seconds, he is traveling at 1 m/s faster than Mary is. Their ratio of speeds is 5:4 so Mary goes 4 m/s and Dan goes 5...