Let's set up equations for the total cost at each jewelry shop based on the number of charms Becky purchases.
Let \( x \) be the number of charms.
Cost at Manchester Fine Jewelry:
The cost for the bracelet is $50, and each charm costs $5. So the total cost can be expressed as:
\[
\text{Cost at Manchester} = 50 + 5x
\]
Cost at Castro Jewelers:
The cost for the bracelet is $10, and each charm costs $9. So the total cost can be expressed as:
\[
\text{Cost at Castro} = 10 + 9x
\]
To find the number of charms \( x \) where the costs are the same, we set the two expressions equal to each other: \[ 50 + 5x = 10 + 9x \]
Now, we'll solve for \( x \):
-
Subtract \( 5x \) from both sides: \[ 50 = 10 + 4x \]
-
Subtract \( 10 \) from both sides: \[ 40 = 4x \]
-
Divide by \( 4 \): \[ x = 10 \]
Therefore, Becky would need to add 10 charms for the cost to be the same at both jewelry shops.