Question

10. A cliff on the seashore is eroding at the rate of 17 centimeters per year. Write and solve an equation to find the number of

years in which the cliff will erode 85 centimeters.

Answer 1

The number of years in which the cliff will erode 85 centimeters are:

• 5 years.

Explanation:

To solve the question in the text, you must create a formula that includes the rate (17 centimeters per year) and a variable representing the time (t), how I show below:

• f(t) = 17t

Where:

• t = time in years

Remember that where are not symbols between two numbers o variables, it means you must multiply (17t actually is 17 * t). Now you only must replace t by years 1 per 1 until obtain the value of 85 (the eroding wanted):

1. f(1) = 17(1) = 17
2. f(2) = 17(2) = 34
3. f(3) = 17(3) = 51
4. f(4) = 17(4) = 68
5. f(5) = 17(5) = 85

How you can see, when the time is equal to 5, the f(t) or the eroding is 85, the value we wanted.