Question

Research shows that Mount Everest grows an average of 4 millimeters each year. How many years will it take to grow 720 millimeters

Answer 1

4 mm / year
720 mm = x years

4x = 720 mm
Divide both sides by 4
x = 180 years

To prove it:

4 mm * 180 years = 720 mm

Answer 2

180 years.

Step-by-step explanation:

To calculate this we will need to make a very simple calculation, called the "rule of three", which is a calculation used to find the ratio of three factors.

If we look at the question above, we will see that Mount Everest grows 4 millimeters per year (so in our calculation we will use the ratio 4 = 1), but we don't know how many years ago Mount Everest will grow 720 millimeters (so in our calculation we will use the proportion 720= x).

This way we will have the calculation:

4 = 1

720 = X

From this, we will imagine a diagonal line and multiply the values at the end of each line. This way we will have:

4 x X = 1x 720

As a result we will have:

4X = 720

Now we will move all numbers to one side and all letters to the other side. Since the number 4 is multiplying the letter X, it will move to the other side dividing the 720. So we have:

X = 720/4.

As a result we will have:

x = 180 years.