Best friends Olivia and Sylivia both get a weekly allowance. Olivia's and Sylvia's allowances are in the ration 2 : 3. If Sylvia gets $21 one week, how much did Olivia get?
The ratio of Olivia's allowance to Sylvia's allowance is 2 : 3.
If Sylvia gets $21, Olivia gets 2/3 * $21 = $<<2/3*21=14>>14. Answer: \boxed{14}.
To find out how much Olivia got, we need to determine the ratio of their allowances first.
The ratio of Olivia's allowance to Sylvia's allowance is given as 2:3.
We can create an equation using this ratio. Let's assume Olivia's allowance is represented by 'x':
2/3 = x/21
To solve for 'x', we can cross-multiply:
3x = 2 * 21
3x = 42
To isolate 'x', we can divide both sides of the equation by 3:
x = 42/3
x = 14
Therefore, Olivia got $14 as her allowance.
To find out how much Olivia got, we need to determine the ratio between their allowances.
The ratio of Olivia's to Sylvia's allowance is 2 : 3. This means that for every 2 parts Olivia receives, Sylvia receives 3 parts.
Given that Sylvia received $21, we can set up a proportion to find the value of each part:
3 parts / $21 = 5 parts / x
We can cross-multiply to solve for x:
3 * x = 21 * 2
3x = 42
Dividing both sides by 3:
x = 14
Therefore, each part is equal to $14.
Since Olivia's allowance is in a 2:3 ratio with Sylvia's, Olivia would receive 2 parts.
To find out how much Olivia got, we can multiply her parts (2) by the value of each part ($14):
2 parts * $14 = $28
Thus, Olivia received $28 as her allowance.