Best friends Olivia and Sylvia both get a weekly allowance. Olivia’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.

Let's represent the ratio of Olivia's and Sylvia's allowances as 2x:3x.

We know that Sylvia gets $21 one week, which represents 3x. So, we can set up the equation 3x = 21.

To find x, we divide both sides of the equation by 3. 3x/3 = 21/3, which simplifies to x = 7.

Now, we can find Olivia's allowance by multiplying her ratio (2x) by x. Olivia gets 2 * 7 = $<<2*7=14>>14. Answer: \boxed{14}.

To find out how much Olivia got as an allowance, we can set up a proportion based on the given ratio.

Let's assume Olivia's allowance as "x" dollars.

According to the ratio 2:3, we can set up the following proportion:

2/3 = x/21

To solve for x, we can cross-multiply:

2 * 21 = 3 * x

42 = 3 * x

Divide both sides by 3 to isolate x:

x = 42/3

x = 14

Therefore, Olivia received $14 as her allowance for that week.

To represent this using a tape diagram, we can draw two separate sections for Olivia and Sylvia's allowances. Since the ratio is given as 2:3, we can divide the tape into two sections with different lengths but in the ratio of 2:3. Olivia's section will be shorter than Sylvia's.

Olivia's tape diagram:
|----|----|

Sylvia's tape diagram:
|----|----|----|

Given that Sylvia received $21 for that week, we can cut Sylvia's tape into three equal parts and determine the value of each part:

|----|----|----| => $21

Now we can compare the lengths of the sections to find Olivia's allowance.

|----|----| => $14

Hence, Olivia received $14 as her allowance.

To solve this problem using a tape diagram, we can represent Olivia's and Sylvia's allowances as two parts of a whole.

Let's start by representing Sylvia's allowance of $21. We can draw a rectangle and divide it into three equal parts. Each part represents $7, since $21 divided by 3 is $7.

*<-----$7----->*<-----$7----->*<-----$7----->*

Now, we need to find Olivia's allowance. The ratio of Olivia's to Sylvia's allowance is 2:3. Since Sylvia's allowance is represented by three parts, we need to use two parts to represent Olivia's allowance.

$7 + $7 = $14

So, Olivia's allowance is $14.