# 1)tickets decreased from $90.00 to $85.002)a $170.00 bicycle decreased to $155.00there are 2 questions.please help me find the percent of decrease for each of the following items.

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Both of these are simple percentage problems. Your percentage formula is, as always:

p/w=%/100

where the part of the whole is equal to the percentage over 100.

So in this case, your part for **number 1** is $5 (the amount decreased) and your whole is $90. Your percentage is unknown, so let's call that **X**. So your re-written formula should be:

$5/$90 = **X**/100

This is a proportion, so we can cross-multiply, so:

$5 x 100 = 500

$90 x **X** = 90**X**

So now we have 90**X** = 500.

In order to isolate **X**, we need to divide 90 from both sides.

90**X** / 90 = **X**

500 / 90 = 5.56

So, X = 5.56, and therefore the price decreased by 5.56%.

For **number 2**, your part is $15, your whole is $170, and again your percentage is unknown, **X**.

$15/$170 = **X**/100

So again, we cross-multiply, and get:

$15 x 100 = 1500

$170 x **X** = 170**X**

And therefore,

1500 = 170**X **

Now we isolate X by dividing out the coefficient from both sides.

170**X** / 170 = **X**

1500 / 170 = 8.82

Therefore, X = 8.82%, your percentage of decrease.

This might be an easier way to think about it.

In the first problem, the amount of decrease is $5. What you need to find is what percent $5 is of $90 (since $90 is the number you started with).

Percent problems can always be solved using:

Part / Whole = %

Just plug in what you know and solve it to find the missing piece. Here, you know the part ($5) and the whole ($90).

So, the % = $5 / $90 = .0555555 etc

Remember that .05 is the same as 5%. So, just round the answer to however many places your teacher wants.

.0555555 etc = .0556 (5.56%) or .056 (5.6%) or .06 (6%) depending on how exact you need to be.

1)tickets decreased from $90.00 to $85.00

90-85=5

5/90 x 100 = **5.55%**

2)a $170.00 bicycle decreased to $155.00

170 - 155 = 15

15/170 x 100= **8.82%**

1) The tickets decreashed from 90 dollars to 85 dollars, so the price change is 5 dollars.

Percentage decrease= decrease/ original amount * 100% so:

% decrease= 5/90 * 100%= **5.55%**

2) The price change is 170-155= 15 dollars

% decrease= 15/170*100%= **8.82%**