220 minus your age is the formula used to find your

Maximum heart rate

Explanation:

Your heart rate is measured in "beats per minute" (BPM), which counts the number of times your heart beats in a minute. The word "maximum" means the most.

Subtracting your age from 220 will give you the most times your heart should beat in a minute.

Example:

If you are 19 years old, you subtract 19 from 220.

220 - 19 = 201

A 19 year-old's maximum heart rate is 201 BPM.

This formula is often used to measure the intensity of exercise. You should aim to increase your heart rate to 55% to 85% of your maximum heart rate. Your maximum heart rate would be 100%.

Example:

For someone who is 19 years old:

55% of max. HR = 0.55(201) = 110.55

85% of max. HR = 0.85(201) = 170.85

They would aim for between 110 and 170 BPM.

      x/140 = 25/100

we need to find the x to find the x multiply 140 and 25

and what do you get 3500.   and what is 3500 divided by 100

= 35