A book's price is decreased by 10% and the new price is $18. What was the origin

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Question: A book\'s price is decreased by 10% and the new price is $18. What was the original price?

Options:

Correct Answer: $20

Solution:

Let the original price be x. Then, x - 0.1x = 18 => 0.9x = 18 => x = 18 / 0.9 = $20.

A book's price is decreased by 10% and the new price is $18. What was the original price?

A book's price is decreased by 10% and the new price is $18. What was the original price?

Step 1: Let the original price of the book be represented by 'x'.
Step 2: When the price is decreased by 10%, the new price is 90% of the original price. This can be written as x - 0.1x = 0.9x.
Step 3: We know the new price is $18, so we can set up the equation: 0.9x = 18.
Step 4: To find the original price 'x', we need to solve the equation. First, divide both sides by 0.9: x = 18 / 0.9.
Step 5: Calculate 18 divided by 0.9, which equals $20. Therefore, the original price of the book is $20.

Percentage Decrease – Understanding how to calculate the original price after a percentage decrease.
Algebraic Manipulation – Using algebra to solve for an unknown variable in an equation.