What is the value of 33a – 2 when a = 2?
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Solution
Plug in 2 for a to find 33(2) – 2 or 36 – 2. When in doubt, expand it out. So, (3 × 3 × 3 × 3 × 3 × 3) – 2 = 729 – 2 = 727.
8z4 = 96
Quantity A | Quantity B |
2 | z |
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Solution
Divide both sides by 8 to get z 4 = 12.Rather than finding the fourth root of 12, try plugging in 2 for z: 24 = 16, so z must be less than 2. Of course, z may be negative, but any negative number is also less than 2.
a < 0
Quantity A | Quantity B |
a2 | 2a |
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Solution
Try Plugging In. If a = –3, then Quantity A is (–3)2 = 9 and Quantity B is 2(–3) = –6. Notice that Quantity A must always be positive because anything raised to an even power is positive. Quantity B must be negative because a positive times a negative is always negative.Thus, Quantity A must always be greater.
A 60 ounce package of trail mix contains x ounces of raisins, x + 8 ounces of peanuts, and 32 ounces of granola. If the ratio of peanuts to granola is 9:16, what is the value of x ?
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Solution
10
Here’s the ratio box you can set up. From the ratio with the granola and the actual ounces of granola provided you can solve for the multiplier, which is 2.
Raisins Peanuts Granola Total ? 9 16 30 2 2 2 2 x x+8 32 60 Multiplying vertically, the number of peanuts is 18.You have 18 = x + 8, so x = 10.
If Elier can bake c cakes in h hours, then at this rate how many hours will it take him to bake 777 cakes?
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Solution
Plug in your own numbers for c and h. Let’s say Elier can bake 14 cakes in 2 hours; this makes c = 14 and h = 2.That means he can bake 7 cakes per hour. At this rate, it will take him 111 hours to bake 777 cakes.Circle 111 as your target number. When you plug in your values, choices (A) and (D) are way too big.Choices (C) and (E) are way too small. Using your calculator, you can determine that choice (B) matches
Mariko can knit 5 rows of a scarf in x minutes. If there are 100 rows in each foot of the scarf, how many hours, in terms of x and y, will it take Mariko to finish a scarf that is y feet long?
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Solution
As soon as you see variables in the answer choices, set up your scratch paper to Plug In. Start with x = 5, so it takes 1 minute to knit 1 row. Now make y = 2. A scarf 2 feet long means Mariko has to knit 200 rows, which will take 200 minutes; since the problem asks how many hours it will take, your target answer is \(\frac{200}{60}=3\frac{1}{3}\). Now plug your values into the answer choices; only choice (A) hits your target.Choices (C) and (E) are clearly too small, and choice (D) is a fraction, so you may not have to calculate all the choices
If a⁄b = \(\frac{11}{6}\) and b⁄c = 4⁄3 , then what is the ratio of a to c ?
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Solution
\(\frac{22}{9}\)
The common element between both proportions is b, so that’s what you’ll want to start with. However, the numerical value of b does not match from proportion to proportion, so you’ll essentially want to find a common multiple for both values of b.Both 4 and 6 are factors of 12, so use 12 as your common multiple. For the first proportion, you’ll need to double it in order to make b = 12. When you do so, a = 22. For the second proportion, you’ll need to triple it to make b = 12.Therefore, c = 9. Now that the two proportions have the same value for b, you know that a:c equals 22:9, which can be written as a fraction.
If the smallest angle of a triangle measures 45 degrees, which of the following could be the ratio of the three angles of the triangle?
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Solution
A,B, D, and F
For each choice, use a ratio box.The first part of each ratio represents 45 degrees. For choice (A), the multiplier will be 45 divided by 2, or 22.5.The ratio adds up to 8 (2 + 3 + 3), so check that 8 × 22.5 = 180. It does, so choice (A) works. For choice (B), based on 3 representing 45 degrees, the multiplier is 15.The ratio adds up to 12, and 12 × 15 = 180, so this choice works as well. Using this approach, choice (C) does not work:The multiplier is again 15, but 15 × 15 does not equal 180.Choice (D) works, with a multiplier of 5: 5 × 36 = 180. When you test the remaining two choices, neither one produces the 180 degrees you need for the triangle, so eliminate them.
In one day, Juan sends Keith three times as many messages as he sends Laurence, and Laurence sends Missy 4.5 times as many messages as he receives from Juan. If Missy received 18 messages from Laurence, how many messages does Keith receive from Juan?
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Solution
It’s an algebra question with numbers for answer choices, so set up your scratch paper to plug in the answers.The answers represent the number of messages Keith receives from Juan, so label them K, or something similar, and give yourself columns for L, which is K ÷ 3, and M, which is 4.5 × L. Start with choice (C). If K = 16, then L is a fraction; since you can send a fractional message, eliminate choice (C)—and go ahead and eliminate choice (E), since it’s also not divisible by 3. Next, try choice (B), since it’s the middle of the remaining 3 answer choices. If K = 12, then L = 4 and M = 18.That’s the correct number of messages for Missy, so choice (B) is correct.
Jenny’s factory produces gear shafts at the rate of 250 gear shafts per hour. She
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Solution
20
Jenny must complete 3000 gear shafts in 10 hours, which is a rate of 300 gear shafts per hour. Percent change is \(\left (\frac{difference}{original} \right )\times 100\). In this case, the difference is 50 and the original is 250, so the percent change is \(\left ( \frac{50}{250} \right )\).The question asks for percent increase, so be sure to enter 20, and not 0.2