The equation for this sequence is:

a_n = a_n-1 + 4(n - 1)

where n is the term's order in the sequence, a_n is the value of the term, and a_n-1 is the value of the term before a_n. This makes the next number:

a₆ = a₅ + 4(6 - 1)
a₆ = 41 + 4(5)
a₆ = 61

A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.

To divide fractions, invert the second fraction and then multiply:

\( \frac{1}{5} \) ÷ \( \frac{4}{8} \) = \( \frac{1}{5} \) x \( \frac{8}{4} \)

To multiply fractions, multiply the numerators together and then multiply the denominators together:

\( \frac{1}{5} \) x \( \frac{8}{4} \) = \( \frac{1 x 8}{5 x 4} \) = \( \frac{8}{20} \) = \(\frac{2}{5}\)

You have 4 out of the total of 150 raffle tickets sold so you have a (\( \frac{4}{150} \)) x 100 = \( \frac{4 \times 100}{150} \) = \( \frac{400}{150} \) = 3% chance to win the raffle.

To find the average of these 4 numbers add them together then divide by 4:

\( \frac{9 + 3 + 7 + 5}{4} \) = \( \frac{24}{4} \) = 6