Add the numbers in base 5.

When adding in base 5, if the sum of digits is 5 or more, we carry over groups of 5.

• Rightmost column: $3 + 3 = 6$. In base 5, $6 = 1 \times 5 + 1$. Write down 1, carry over 1.
• Middle column: $2 + 4 + 1 (\text{carry}) = 7$. In base 5, $7 = 1 \times 5 + 2$. Write down 2, carry over 1.
• Leftmost column: $1 + 1 (\text{carry}) = 2$. Write down 2.

The sum is $221_{\text{five}}$.

• The final answer is $\boxed{221_{\text{five}}}$.

c) Given that $12_y = 7_{\text{ten}}$. Find the value of base $y$.

• The final answer is $\boxed{5}$.

24. The sum of 3 consecutive counting numbers is 63. Find the numbers.

The three consecutive counting numbers are $n$, $n+1$, and $n+2$.

The numbers are $n$, $n+1$, $n+2$.
20, $20+1$, $20+2$.
20, 21, 22.

• The final answer is $\boxed{20, 21, 22}$.

25. In a group of 50 farmers, $\frac{2}{5}$ grow crops and the rest rear animals.

a) Find the fraction of the farmers that rear animals.

Subtract the fraction that grow crops from 1 to find the fraction that rear animals.

• The final answer is $\boxed{\frac{3}{5}}$.

b) How many farmers grow crops?

• The final answer is $\boxed{20 \text{ farmers}}$.

c) How many more farmers rear animals than grow crops?

From part a), the fraction rearing animals is $\frac{3}{5}$.

• The final answer is $\boxed{10 \text{ farmers}}$.