Math Problem Statement

work out

Sam runs around her athletics track. After running some laps, she has done one fifth of her target. After another two laps, she has done a quarter of her target. What is her target number of laps?

Solution

Let's define the target number of laps as xx.

Step 1: Information from the problem

  • After running some laps, Sam has completed one-fifth of her target, which means she has completed 15\frac{1}{5} of xx, or x5\frac{x}{5} laps.
  • After running 2 more laps, she has completed one-quarter of her target, which is x4\frac{x}{4} laps.

Step 2: Setting up the equation

Let L1L_1 be the number of laps Sam initially ran before running the additional 2 laps:

  • After the additional 2 laps, she has completed L1+2=x4L_1 + 2 = \frac{x}{4}.
  • From the first part of the problem, L1=x5L_1 = \frac{x}{5}.

Substitute L1=x5L_1 = \frac{x}{5} into the second equation: x5+2=x4\frac{x}{5} + 2 = \frac{x}{4}

Step 3: Solving the equation

Now, solve for xx: x5+2=x4\frac{x}{5} + 2 = \frac{x}{4} Subtract x5\frac{x}{5} from both sides: 2=x4x52 = \frac{x}{4} - \frac{x}{5} To combine the fractions on the right-hand side, find a common denominator: 2=5x204x202 = \frac{5x}{20} - \frac{4x}{20} 2=x202 = \frac{x}{20} Multiply both sides by 20 to solve for xx: x=40x = 40

Conclusion:

Sam's target number of laps is 40.

Would you like more details on the solution, or do you have any questions?

Here are 5 related questions you might explore:

  1. How many laps had Sam run initially, before the additional 2 laps?
  2. What fraction of the target had Sam completed after the 2 additional laps?
  3. How would the target number of laps change if the fraction completed was different?
  4. What if Sam had run 3 laps instead of 2 in the second part of the problem?
  5. How would you set up the equation if the fractions in the problem were different, say one-third and one-fifth?

Tip: Always check your units and variables carefully when translating word problems into equations!

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Math Problem Analysis

Mathematical Concepts

Algebra
Fractions
Equations

Formulas

Fraction of target laps: 1/5 and 1/4
Basic linear equation

Theorems

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Suitable Grade Level

Grades 6-8