A) Change 1(1)/(5) as a percentage.

The percentage is $\boxed{120\%}$.

b) Find the smallest number that can be divided by $48, 32$ and 40.

This requires finding the Least Common Multiple (LCM) of $48, 32,$ and 40.

Highest power of 2: $2^5$
Highest power of 3: $3^1$
Highest power of 5: $5^1$

The smallest number is $\boxed{480}$.

c) Find the next number in the series below: $2, 3, 5, 7, 9, \_$

$3 - 2 = 1$
$5 - 3 = 2$
$7 - 5 = 2$
$9 - 7 = 2$

The differences are $1, 2, 2, 2$. After the first term, each subsequent term is found by adding 2 to the previous term.

The next number is $9 + 2 = 11$.
The next number is $\boxed{11}$.

4.

a) Find the square of $3^2$.

The square of $3^2$ is $\boxed{81}$.

b) Calculate $\sqrt{441} - \sqrt{256}$.

The result is $\boxed{5}$.

c) Write 0.75 as a simple fraction.

The simple fraction is $\boxed{\frac{3}{4}}$.

5.

a) The bus started the journey from Sumbawanga at $1220$hours and arrived in Tabora at $1855$hours. How long did the bus take to travel from Sumbawanga to Tabora?

Start time: 12 hours 20 minutes
End time: 18 hours 55 minutes

Subtract minutes: $55 \text{ minutes} - 20 \text{ minutes} = 35 \text{ minutes}$.
Subtract hours: $18 \text{ hours} - 12 \text{ hours} = 6 \text{ hours}$.
The bus took $\boxed{6 \text{ hours and } 35 \text{ minutes}}$.

b) A chicken hatches a chick after incubating eggs for 21 days. What is this duration in hours?

There are 24 hours in 1 day.

The duration in hours is $\boxed{504 \text{ hours}}$.