Test Prep OAT Online Practice Questions and Exam Preparation

Test Prep OAT Online Questions & Answers

• Question 131:

  Three consecutive prime numbers add up to 223. What is the smallest of these numbers?

  A. 61
  B. 67
  C. 68
  D. 71
  E. 79
  D. 71

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  Begin tackling these problems by first looking at the answer choices. One can eliminate `68' immediately because it is not a prime number. From there, pick an answer choice and work from there. Because the question asks for the first number in the set of 3 prime numbers, it means you pick an answer choice, and then figure out the next two prime numbers that follow it. Add them up and see if they add up to 223. With 71, the next two prime numbers will be 73 and 79. 71 + 73 + 79 = 223.

• Question 132:

  A mythical atom has isotopes: 10X, 11X and 12X with masses 10, 11, and 12 respectively. 10X has an abundance of 80%, 11X of 15% and 12X of 5%. What is the atomic mass of this X atom?

  A. 10
  B. 10.25
  C. 10.75
  D. 11
  E. 11.25
  B. 10.25

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  Logically you should be aware the answer is going to be a low 10 number due to the vast abundance of the 10 atom. However, to calculate it mathematically: (0.80 × 10) + (0.15 × 11) + (0.05 × 12) = 10.25

• Question 133:

  Cyanide is a poison that binds to the active site of the enzyme cytochrome c and prevents its activity. Cyanide is a(n)

  A. Prosthetic group
  B. Cofactor
  C. Reverse regulator
  D. Coenzyme
  E. Inhibitor
  E. Inhibitor

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  Enzyme inhibitors attach to an enzyme and block substrates from entering the active site, thereby preventing enzyme activity. As stated in the question, cyanide is a poison that irreversibly binds to an enzyme and blocks its active site, thus fitting the definition of an enzyme inhibitor.

• Question 134:

  A man decided to buy new furniture from Futuristic Furniture for $2600. Futuristic Furniture gave the man two choices: pay the entire amount in one payment with cash, or pay $1000 as a down payment and $120 per month for two full years in the financial plan. If the man chooses the financial plan, how much more would he pay?

  A. $1480 more
  B. $1280 more
  C. $1600 more
  D. $2480 more
  B. $1280 more

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  Multiply $120 by 24 months (a full two years) to get $2880. Add the thousand dollars for the down payment to get $3880. Find the difference between the entire amount all at once ($2600) and the amount paid in the plan ($3880). To find the difference, you subtract. The difference shows that $1280 more is paid with the installment plan.

• Question 135:

  You are interested in extracting a specific carboxylic acid only in a mixture containing amines, ketones and phenols. Which of the following can be used to accomplish this?

  A. NaOH
  B. HCl
  C. NaHCO3
  D. H2O
  E. A and C
  C. NaHCO3

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  This is an organic lab question that deals with extraction. In order to extract the carboxylic acid only, you can only use sodium bicarbonate. Although NaOH is capable of extracting the carboxylic acid, it will also extract the phenol, which is not what the question asks.

• Question 136:

  Rank the following in the correct order of increasing wavelength:

  A. X-rays, Gamma rays, Visible light, Radio waves, UV
  B. Gamma rays, X-rays, Infrared, UV, Radio waves
  C. Radio waves, Infrared, UV, X-rays, Gamma rays
  D. X-rays, Gamma rays, UV, Infrared, Radio waves
  E. Gamma rays, X-rays, UV, Infrared, Radio waves
  E. Gamma rays, X-rays, UV, Infrared, Radio waves

• Question 137:

  What is the solution for the equation x / 3 + 4 = 7

  A. 12
  B. 21
  C. 15
  D. 9
  D. 9

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  x / 3 + 4 = 7, x / 3 = 3, x = 9.

• Question 138:

  Which of the answer choices represents a group containing a metal, metalloid and nonmetal elements?

  A. Calcium, Nickel, Carbon
  B. Potassium, Neon, Hydrogen
  C. Lithium, Hydrogen, Silicon
  D. Hydrogen, Oxygen, Silicon
  E. Cesium, Boron, Silicon
  C. Lithium, Hydrogen, Silicon

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  Periodic trends such as ionization energy, electronegativity, atomic radii, basicity etc. are very important to know as they are commonly tested topics. It is also important to recognize the groups in the periodic table such as the Metals, Nonmetals and Metalloids. Only choice (C) provides an element from each group. Lithium (Metal), Hydrogen (Non-metal) and Silicon (Metalloid).

• Question 139:

  A 1-gallon bottle containing 20% apple juice is mixed with a 2-gallon bottle containing 30% apple juice. What is the percentage of apple juice in the 3-gallon mixture?

  A. 23%
  B. 27%
  C. 30%
  D. 50%
  E. 59%
  B. 27%

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  This question can be solved in numerous ways. If 1 gallon has 20% apple juice, it means apple juice consists of 0.2 gallons. If the 2 gallon has 30% apple juice, it means apple juice consists of 0.6 gallons. Thus, there are a total of 0.8 gallons of apple juice in the mixture of the total 3 gallons.

  Find the percentage: (0.8 gallons of apple juice / 3 total gallons) × 100 = ~27%

• Question 140:

  A bowling ball with a mass of 4 kilograms moving at a speed of 10 meters per second hits a stationary 1 kg bowling ball in a head-on elastic collision. What is the speed of the stationary ball after the collision?

  A. 0 m/s
  B. 10 m/s
  C. Less than 10 m/s, but not 0 m/s
  D. More than 10 m/s
  D. More than 10 m/s

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  Since this is a head-on elastic collision, you could use conservation of kinetic energy and momentum to actually solve this problem. However, in this case, you only need to think through the answers to arrive at a correct conclusion. Clearly the ball after it's struck won't be going 0 m/s. And since this is an elastic collision, and it is hit by a much larger ball, it must be going faster than the larger ball was originally moving. Therefore, the ball will be moving at more than 10 m/s. If this were an inelastic collision where the balls stuck together, the ball would final velocity would be less than 10 m/s.