r = 20 p = r^2 + 50 M1: For method to find missing value of p, p = (20)^2 + 50 M1: For method to find the missing value of r, e.g., 100 = p - 50: 100 = p - 50 M1: For finding both missing values of p: p = 20^2 + 50 A1: 450 - Edexcel - GCSE Maths - Question 13 - 2022 - Paper 1

To find r when we set p = 100, we can rearrange the equation:

$100 = p - 50$

Thus,

$p = 100 + 50 = 150$

Now using the original equation, we find r:

$150 = r^2 + 50$

Rearranging, we have:

$r^2 = 150 - 50 = 100$

Finally, solving for r gives:

$r = ext{sqrt}(100) = 10$

Using the initial equation:

$p = r^2 + 50$

For both values we found:

1. If r = 20, then p = 450,
2. If we solved 100 = p - 50, we found p as 150.

Both calculations yield different p values based on varying r.