Question

St. Augustine grass can grow at the rate of 4 over 7 centimeter per week.

Answer 1

Given, the rate of growth of St. Augustine grass is $\frac{4}{7}$ cm per week.

We have to find the number of weeks that the grass grow to $\frac{12}{7}$ cm.

Let's take the number of weeks be x.

In 1 week the grass grow = $\frac{4}{7}$ cm

So in x weeks the grass grow = $(\frac{4}{7}) (x) =\frac{4x}{7}$ cm

So we can write,

$\frac{4x}{7} =\frac{12}{7}$

To solve it for x, first we will move 7 to the right side by multiplying it to both sides. We will get,

$(\frac{4x}{7}) (7) =(\frac{12}{7})(7)$

$4x =(\frac{12}{7})(7)$

$4x = 12$

Now to get we will move 4 to the right side by dividing it to both sides. We will get,

$\frac{4x}{4} =\frac{12}{4}$

$x = 3$

So we have got the required answer.

After 3 weeks the grass grow $\frac{12}{7} cm$.