The ratio of pears to green apples is 1:3, meaning for every 1 pear, there are 3 green apples.

You are given that there are 150 green apples, and we need to find how many pears there are.

To find the number of pears, we can set up the ratio:

$\frac{1 \text{ pear}}{3 \text{ green apples}} = \frac{x \text{ pears}}{150 \text{ green apples}}$

Now, cross-multiply to solve for $x$:

$1 \times 150 = 3 \times x$

$150 = 3x$

Now, divide both sides by 3:

$x = \frac{150}{3} = 50$

So, there are 50 pears.

Would you like more details or have any questions about this?

Here are some related questions you can explore:

1. How do you solve proportions like this one?
2. How do ratios apply to real-life situations, like cooking or mixing ingredients?
3. What happens to the ratio if there were 200 green apples instead of 150?
4. How do you interpret inverse ratios (like 3:1)?
5. Can you solve this problem using algebraic equations?

Tip: When working with ratios, remember that they represent relative relationships, not absolute values. You can scale up or down by multiplying or dividing.