Every doubt.
Every practice.
One study lab.

Step 1: Find a, b and c

Compare with $ax^2 + bx + c = 0$.

Step 2: Find the discriminant

The discriminant tells us how many real roots there are.

Step 3: Use the quadratic formula

Since $D > 0$, there are two different real roots.

Step 4: Find both roots

Step 1: Given (in SI units)

Step 2: Formula used

Coulomb's law.

Step 3: Substitution

Put every value in.

Step 4: Calculation

Work out the numbers and the powers of 10 separately.

Step 1: Open and read the file

Open story.txt in read mode and read the whole text into a variable.

f = open("story.txt", "r")
data = f.read()

Step 2: Count with a loop

Check every character; add 1 when it is 'a'. (The board answer uses a loop, not count().)

count = 0
for ch in data:
    if ch == 'a':
        count += 1

Step 3: The full function

Print the result, close the file, and call the function.

def COUNT_A():
    f = open("story.txt", "r")
    data = f.read()
    count = 0
    for ch in data:
        if ch == 'a':
            count += 1
    print("Total a:", count)
    f.close()

COUNT_A()

Step 1: Write the numbers

Consecutive numbers go up by 1.

Step 2: Make the equation

Their sum is 51.

Step 3: Solve it

Subtract 3, then divide by 3.