Math Practice Problems Review

Mathematical Problems Overview

Problem 1: Percentage Calculation

  • Question: If 2% of a number is 8, what is that number?

    • Options:

    • A. 79\frac{7}{9}

    • B. 23\frac{2}{3}

    • C. 811\frac{8}{11}

    • D. 912\frac{9}{12}

    • E. 710\frac{7}{10}

    • Explanation: To find the original number, use the equation:
      0.02×x=80.02 \times x = 8
      Solving for x gives:
      x=80.02=400x = \frac{8}{0.02} = 400

    • Therefore, the correct answer is not listed in the options.

Problem 2: Finding the Smallest Whole Number

  • Question: Find the smallest whole number larger than the sum of 22 + 3 + 41.

    • Calculation:
      22+3+41=6622 + 3 + 41 = 66

    • Options:

    • A. 0.16

    • B. 4

    • C. 16

    • D. 400

    • E. 800

    • Conclusion: The answer is 67, not among the options listed.

Problem 3: Sum of Page Numbers

  • Question: When I open my math book, two pages face me, and the sum of their two page numbers is 317. What is the number of the very next page?

    • Explanation: Let the two pages be pp and p+1p + 1:

    • p+(p+1)=317p + (p + 1) = 317

    • This implies 2p+1=3172p + 1 = 317

    • Simplifying gives: 2p=3162p = 316, hence p=158p = 158.

    • Next page number: 159.

  • Options:

    • A. 9

    • B. 10

    • C. 11

    • D. 12

    • E. 13

    • Correct answer: The next page (160) is not an option.

Problem 4: Range of an Expression

  • Question: In what range does the value of the following expression occur? 62+72\sqrt{62} + 72

  • Options:

    • A. 158

    • B. 159

    • C. 160

    • D. 161

    • E. 162

  • Calculation:

    • Approximating:

    • 627.877.87+72=79.87\sqrt{62} \approx 7.87 \Rightarrow 7.87 + 72 = 79.87.

    • The value does not seem to correlate with the provided options.

Problem 5: Factory Shift Times

  • Question: A factory runs nonstop for three 14-hour shifts, starting with the first shift at 9:00 AM. What time does the third shift end?

  • Calculation:

    • First shift: 9:00 AM to 11:00 PM (14 hours)

    • Second shift: 11:00 PM to 1:00 PM (next day)

    • Third shift: 1:00 PM to 3:00 AM (next day)

  • Options:

    • A. 12:00 PM

    • B. 1:00 AM

    • C. 2:00 AM

    • D. 3:00 AM

    • E. 4:00 AM

  • Correct answer: D. 3:00 AM.

Problem 6: Profit Calculation in Grocery Store

  • Question: Maria's Grocery Store buys grapefruits at a cost of 5 for a dollar and sells them at a price of 5 for three dollars. How many must they sell to make a profit of ten dollars?

  • Calculation:

    • Cost for 5 grapefruits: 1 dollar

    • Revenue from 5 grapefruits: 3 dollars

    • Profit per 5 grapefruits: 3 - 1 = 2 dollars

    • To find how many sets of 5 grapefruits are needed to reach a $10 profit:

    • 102=5\frac{10}{2} = 5

    • Hence, they must sell 5×5=255 \times 5 = 25 grapefruits in total to achieve a profit of $10.

  • Options:

    • A. <6

    • D. 8 to 9

Problem 7: Absolute Value Calculation

  • Question: Solve the following: 12(2)2(2)312 - (-2)^2 - (-2)^3

  • Calculation:

    • Simplifying:

    • (2)2=4(-2)^2 = 4

    • (2)3=8(-2)^3 = -8

    • Thus:

    • 124(8)=124+8=1612 - 4 - (-8) = 12 - 4 + 8 = 16

  • Options:

    • A. 0

    • B. 2

    • C. 4

    • D. 6

    • E. 8

  • Correct answer: Not indicated in a way that matches any options.

Problem 8: Custom Operation Definition

  • Question: If A # B means the same thing as 2AB2A - B, then what does 1 # ((2 # 3) # 4) equal?

  • Calculation Sequence:

    • First, calculate:

      • 2 # 3 = 2(2) - 3 = 4 - 3 = 1

    • Then:

      • 1 # 4 = 2(1) - 4 = 2 - 4 = -2

  • Options:

    • A. 15

    • B. 17

    • C. 19

    • D. 20

    • E. 25

Problem 9: Hockey Standings Points Calculation

  • Question: In hockey standings, a win counts for 2 points, a tie for 1 point, and a loss for 0 points. The Devils won 5, lost 4, and tied 1 game in their first 10 games. If they continue at that rate, how many points will they have after 80 games?

  • Calculation:

    • Points from 5 wins: 5×2=105 \times 2 = 10

    • Points from 1 tie: 1×1=11 \times 1 = 1

    • Total points from 10 games: 10+1=1110 + 1 = 11

    • They will repeat this pattern in 80 games, hence:
      8010×11=8×11=88\frac{80}{10} \times 11 = 8 \times 11 = 88

  • Options:

    • A. 4

    • B. 2

    • C. 0

    • D. -2

    • E. -4

  • Correct answer: D. 88.