Best friends Olivia and Sylvia both get a weekly allowance. Oliva’s and Sylvia’s allowances are in the ratio 2:3. If Sylvia gets $21 one week, how much did Olivia get? Use a tape diagram to help organize your thinking.

1 answer

To solve the problem using the given ratio of Olivia's and Sylvia's allowances, we can set up a tape diagram to represent their allowances.

  1. Understanding the Ratio: Olivia and Sylvia’s allowances are in the ratio \(2:3\). This means for every 2 parts that Olivia gets, Sylvia gets 3 parts.

  2. Setting Up the Parts: Let's represent Olivia's allowance as \(2x\) and Sylvia's allowance as \(3x\), where \(x\) is the common multiple for their allowances.

  3. Sylvia's Allowance: We know that Sylvia gets $21 one week. According to our representation, this can be written as: \[ 3x = 21 \]

  4. Finding \(x\): To find \(x\), we can divide both sides of the equation by 3: \[ x = \frac{21}{3} = 7 \]

  5. Calculating Olivia's Allowance: Now that we have \(x\), we can find Olivia's allowance: \[ 2x = 2 \times 7 = 14 \]

  6. Conclusion: Therefore, Olivia's allowance is $14.

Tape Diagram Representation:

To visualize this with a tape diagram:

Olivia's Allowance:      |---|---|  (2 parts for Olivia)
Sylvia's Allowance:      |---|---|---|---|---|  (3 parts for Sylvia)
  • Each part in the diagram represents $7 (the value of \(x\)).
  • Olivia has 2 parts (2 x 7 = $14).
  • Sylvia has 3 parts (3 x 7 = $21).

Thus, Olivia received $14.