Step 1: Interpret the Problem

Calculating the patient’s original heart rate before the drop requires some manipulation of the percentages. We need to consider that the original heart rate represents 100%. If the original heart rate represents 100% we must calculate how much of the original heart rate is remaining after a percent drop.

Given the heart rate dropped by 30%, we know,

100%–30%=70%

Therefore, the remaining heart rate percent is 70%.

Step 2: Turn The Percent Into a Decimal
We never use percentages in our actual math problems, so we first must turn our percentages into a decimal.
To turn a percentage into a decimal, we divide by 100, which is the same as moving the decimal point two spaces to the left.

70%=70.%

70.%÷100=0.70

70%as a decimal is 0.70. Remember, zeros at the end of a number after a decimal does not add any value, so we can just write it as .70.

0.70=0.7

Step 3: Determine the Original Heart Rate
We know 63=70%, and we are looking for the value that represents 100%. This means whatever 100% is, will be more than 63.

Once you calculate the percent paid and turn that into a decimal, we can use the rule below to calculate the original price of an item by using division.

CurrentHeartRate÷Decimal=OriginalHeartRate

63÷0.7=90

The patient’s heart rate before the drop was 90 beats per minute.