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<p>how do you do this question?</p>
<p>Time for substitution. But, before moving to that step, let’s put it out in simpler terms.
I am going to run. For each lap I make, I am going to get P pledges…make that 5 pledges. Each is going to be worth C cents…make that 5 cents. Alright, for each lap I run, I’m going to get 5 x 5 = 25 cents, cool. A mile is 4 laps. I’ve made D dollars…make that 1 dollar. How many miles have I run? Well, if I made only 1 dollar, that means I made 4 laps right? (Each lap gives me 25 cents). And if I ran 4 laps, that means I ran 1 mile. OK, we have our answer: 1. Let’s substitute in the answer choices, keeping in mind that p=5, c=5, d=1. OK, answer choice A:
25(1) / 5 x 5 = 25 / 25 = 1. We have the correct answer, choice A.</p>
<p>If you don’t like substitution and prefer algebra, then ignore the above text, and wait for an algebraic elaboration.</p>
<p>He raises d dollars, which is equal to 100d cents which is equal to pcl. So the number of laps he runs is 100d/pc. Converting laps to miles divide by 4 – so 25d/pc.</p>
<p>With all due respect to fogcity’s approach, but I generally find substitution much more guaranteed and safe. You can use substitution in any question with symbols - ANY question. That saves you the effort of figuring out how values relate to each other, dividing/multiplying different symbols etc. With substitution, you’re guaranteed never to fall for a question like this again. Plausibly, it make take a few seconds more than the straight algebraic approach, but that’s only if you understand how you are going to apply the algebra, for it doesn’t come directly for most (I assume some will argue some) people; time is something that can be worked on, and sooner or later you’ll find yourself substituting, and bypassing these questions in approximately 10-15 seconds, tops.</p>
<p>Good luck!</p>
<p>errr so could i just use random numbers</p>
<p>;</p>
<p>As long as you use those same numbers when backplugging into the answer choices, yeah. But try to go for numbers that are easy to work out, like the ones Mony conviniently picked to make 1 lap and 1 dollar just to make everything easier.</p>