# Thread: Am I doing this right? Inequality question

1. ## Am I doing this right? Inequality question

In a typical year, a willow tree grows 3.5 feet, while a Chitalpa tree grows 2 feet. Suppose a 6-foot willow tree and a 13-foot Chitalpa tree were planted at the same time.

1. Write an inequality to describe when the willow tree is taller.

in writing the inequality I did this:

6 + 3.5y < 13 + 2y

Did I understand this right?

2. ## Re: Am I doing this right? Inequality question

turn your inequality sign the other way ...

3. ## Re: Am I doing this right? Inequality question

Thank you for the quick reply. Is it because the willow tree grows at a faster rate than the Chitalpa?

4. ## Re: Am I doing this right? Inequality question

the question says ...

Write an inequality to describe when the willow tree is taller.
... the left side of the inequality is the height of the willow tree as a function of years, y.

5. ## Re: Am I doing this right? Inequality question

so the inequality correctly stated is:

6 + 3.5y > 13 + 2y

If I want to solve this:

1.5y > 7

1.5/1.5y > 1.5 /7

y > 4.67

I don't know why, but it doesn't look right to me. I am trying to understand this. Does that mean in 4.67 years the Willow tree will be at even height of the Chitalpa?

6. ## Re: Am I doing this right? Inequality question

yes, and when y > 4.67, it will be taller