Math Problem Statement

Quarters weigh 6 grams while dimes weigh 2 grams. Jenny has 5.35 worth of quarters and dimes in her pocket, and altogether weighing a total of 124 grams. How many dimes does Jenny have?

Solution

Let's denote:

  • qq as the number of quarters.
  • dd as the number of dimes.

We have two key pieces of information:

  1. The total value of the coins is $5.35.
  2. The total weight of the coins is 124 grams.

Step 1: Set up the equations

  1. Value equation:

    • Each quarter is worth $0.25, and each dime is worth $0.10.
    • The total value is $5.35, so: 0.25q+0.10d=5.350.25q + 0.10d = 5.35 Multiply through by 100 to eliminate decimals: 25q+10d=53525q + 10d = 535
  2. Weight equation:

    • Each quarter weighs 6 grams, and each dime weighs 2 grams.
    • The total weight is 124 grams, so: 6q+2d=1246q + 2d = 124 Divide this equation by 2 to simplify: 3q+d=623q + d = 62

Step 2: Solve the system of equations

We now have the system of equations:

  1. 25q+10d=53525q + 10d = 535
  2. 3q+d=623q + d = 62

Solve the second equation for dd:

d=623qd = 62 - 3q

Substitute this expression for dd into the first equation:

25q+10(623q)=53525q + 10(62 - 3q) = 535 Simplify: 25q+62030q=53525q + 620 - 30q = 535 5q+620=535-5q + 620 = 535 5q=535620-5q = 535 - 620 5q=85-5q = -85 q=17q = 17

Find dd using q=17q = 17:

d=623(17)d = 62 - 3(17) d=6251d = 62 - 51 d=11d = 11

Conclusion:

Jenny has 11 dimes.

Would you like more details or have any questions?


Here are 5 related questions:

  1. What if Jenny had $6.00 instead of $5.35?
  2. How many coins in total does Jenny have?
  3. What if the total weight was only 100 grams?
  4. What if the quarters weighed 5 grams instead of 6 grams?
  5. How much would the total value be if Jenny had 20 dimes?

Tip: Always check the units and ensure consistency when solving word problems involving money and weight!

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Linear Equations

Formulas

0.25q + 0.10d = 5.35
6q + 2d = 124
25q + 10d = 535
3q + d = 62

Theorems

Solving a system of linear equations

Suitable Grade Level

Grades 8-10