Math Problem Statement

A variety of algebraic problems, including ratios, inequalities, functions, simplifying expressions, and solving equations.

Solution

I'll solve a few of the problems here, starting from the top. Let's go through the initial ones together.

Problem 1

The ratio of good guys to bad guys was 15 to 4. If there were 75 good guys, how many bad guys were there?

  1. Set up the proportion: good guysbad guys=154\frac{\text{good guys}}{\text{bad guys}} = \frac{15}{4}

  2. Use 75 as the number of good guys: 75bad guys=154\frac{75}{\text{bad guys}} = \frac{15}{4}

  3. Solve for the number of bad guys: Cross-multiply: 75×4=15×bad guys75 \times 4 = 15 \times \text{bad guys} 300=15×bad guys300 = 15 \times \text{bad guys} bad guys=30015=20\text{bad guys} = \frac{300}{15} = 20

Answer: There were 20 bad guys.


Problem 2

The ratio of blue marbles to green marbles was 17 to 5. If there were 110 marbles in the bag, how many were blue marbles?

  1. Let xx be the number of blue marbles and yy be the number of green marbles.

  2. Set up the system using the total and the ratio: x+y=110x + y = 110 xy=175\frac{x}{y} = \frac{17}{5}

  3. Express yy in terms of xx: y=517xy = \frac{5}{17}x

  4. Substitute y=517xy = \frac{5}{17}x into x+y=110x + y = 110: x+517x=110x + \frac{5}{17}x = 110 22x17=110\frac{22x}{17} = 110 x=110×1722=85x = \frac{110 \times 17}{22} = 85

Answer: There were 85 blue marbles.


Problem 3

Bob and Nigel found that 4 times the sum of a number and -5 equals 24. What is the number?

  1. Set up the equation: 4(x+(5))=244(x + (-5)) = 24 Simplify: 4(x5)=244(x - 5) = 24

  2. Solve for xx: Divide both sides by 4: x5=6x - 5 = 6 Add 5 to both sides: x=11x = 11

Answer: The number is 11.


Problem 4

If the product of a number and -5 is reduced by 2, the result is 26 less than twice the opposite of the number. What is the number?

  1. Set up the equation: Let the number be xx. Then, the equation is: 5x2=2(x)26-5x - 2 = 2(-x) - 26

  2. Simplify and solve for xx: Expand and simplify: 5x2=2x26-5x - 2 = -2x - 26 Add 5x5x to both sides: 2=3x26-2 = 3x - 26 Add 26 to both sides: 24=3x24 = 3x Divide by 3: x=8x = 8

Answer: The number is 8.


Would you like more details on any of these solutions, or help with the next set of problems?


Here are 5 related questions to expand on these types of problems:

  1. How do you set up a proportion when given two parts and the whole?
  2. What steps can be taken to solve ratios with multiple unknowns?
  3. How can you create an equation from a word problem involving "the product of a number"?
  4. Why is it necessary to isolate variables when solving equations?
  5. What other methods can be used to solve proportions besides cross-multiplying?

Tip: When translating word problems to equations, identify keywords (like "product," "sum," and "difference") to understand the operations involved.

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Math Problem Analysis

Mathematical Concepts

Ratios and Proportions
Inequalities
Functions
Exponentiation
Simplification of Expressions
Solving Equations
Perimeter and Volume Calculation

Formulas

Proportion formula: a/b = c/d
Area and perimeter of geometric shapes
Volume of a prism: V = Base Area * Height
Solving linear equations: ax + b = c
Exponent rules: a^m * a^n = a^(m+n)

Theorems

Distributive Property
Exponent Laws
Basic Ratio and Proportion principles

Suitable Grade Level

Grade 8-10