What is the index form of 333556677888?

Sum $= 1 + 8 + 3 + 0 + 0 + 9 + 1$.

Sum $= 22$.

16. If I borrowed the sum of 5000 FRS for 6 months at 4% per annum. How much will I pay as interest?

Principal (P) $= 5000$ FRS.
Rate (R) $= 4\%$ per annum $= \frac{4}{100} = 0.04$.
Time (T) $= 6$ months $= \frac{6}{12}$ years $= 0.5$ years.

Interest (I) $= P \times R \times T$.

$I = 5000 \times 0.04 \times 0.5$
$I = 200 \times 0.5$
$I = 100$ FRS.

17. The index form of 33377722 is $3^3 7^3 2^2$. What is the index form of 333556677888?

The "index form" here means grouping identical digits and writing them as a base raised to the power of their count.
For 33377722: three $3$s ($3^3$), three $7$s ($7^3$), two $2$s ($2^2$).

Count the occurrences of each digit:

• Digit 3 appears 3 times $\rightarrow 3^3$
• Digit 5 appears 2 times $\rightarrow 5^2$
• Digit 6 appears 2 times $\rightarrow 6^2$
• Digit 7 appears 2 times $\rightarrow 7^2$
• Digit 8 appears 3 times $\rightarrow 8^3$

The index form is $3^3 5^2 6^2 7^2 8^3$.

18. 4 decreased by 50% is 2. Decrease 45000 FRS by 8%.

Decrease amount $= 8\%$ of 45000.
Decrease amount $= \frac{8}{100} \times 45000 = 8 \times 450 = 3600$ FRS.

New amount $= 45000 - 3600 = 41400$ FRS.

19. A rectangle measures 6m by 5m. Find its area.

Area $= \text{length} \times \text{width}$.

Length $= 6\text{m}$
Width $= 5\text{m}$

Area $= 6\text{m} \times 5\text{m} = 30\text{m}^2$.

20. There are 80 0.25s in 20. How many 0.25s are in 16?

Number of $0.25$s $= \frac{16}{0.25}$.

$0.25 = \frac{1}{4}$.
So, $\frac{16}{0.25} = \frac{16}{\frac{1}{4}} = 16 \times 4$.

$16 \times 4 = 64$.