You have R18.50 and two of your friends have R12.42 and R15.03. How much more money do you need to hire a taxi for a trip that costs R50?

Round each amount to the nearest whole number.
Your money: $\text{R}18.50 \approx \text{R}19$
Friend 1's money: $\text{R}12.42 \approx \text{R}12$
Friend 2's money: $\text{R}15.03 \approx \text{R}15$
Taxi cost: $\text{R}50$

Estimated total money available:

$$\text{R}19 + \text{R}12 + \text{R}15 = \text{R}46$$

Estimated money still needed:

$$\text{R}50 - \text{R}46 = \text{R}4$$

$$\text{Total available money} = \text{R}18.50 + \text{R}12.42 + \text{R}15.03$$ $$\text{Total available money} = \text{R}45.95$$

$$\text{Money needed} = \text{Taxi cost} - \text{Total available money}$$ $$\text{Money needed} = \text{R}50.00 - \text{R}45.95$$ $$\text{Money needed} = \text{R}4.05$$

Add the money needed to the total available money to ensure it equals the taxi cost.

$$\text{R}45.95 + \text{R}4.05 = \text{R}50.00$$

This matches the taxi cost.

You need to collect an additional $\boxed{\text{R}4.05}$.

: Fruit Juice Mixture

• Question: Your mother is mixing fruit juice for a party. The container can hold 20 litres. She pours in 10.4 litres of soda, 3.63 litres of lime juice and 2.4 litres of pineapple juice. How much orange juice can she still pour in?

$$\text{Volume poured} = 10.4\,\text{L} + 3.63\,\text{L} + 2.4\,\text{L}$$ $$\text{Volume poured} = 16.43\,\text{L}$$

$$\text{Remaining capacity} = \text{Total container capacity} - \text{Volume poured}$$ $$\text{Remaining capacity} = 20.00\,\text{L} - 16.43\,\text{L}$$ $$\text{Remaining capacity} = 3.57\,\text{L}$$

She can still pour in $\boxed{3.57\,\text{L}}$ of orange juice.

: Shopping for Clothes

• Question: You buy two shirts for R35.20 each and a cap. How much did the cap cost if you get R2.44 change from a R100 note?

$$\text{Cost of shirts} = 2 \times \text{R}35.20$$ $$\text{Cost of shirts} = \text{R}70.40$$

$$\text{Total spent} = \text{R}100.00 - \text{R}2.44$$ $$\text{Total spent} = \text{R}97.56$$

$$\text{Cost of cap} = \text{Total spent} - \text{Cost of shirts}$$ $$\text{Cost of cap} = \text{R}97.56 - \text{R}70.40$$ $$\text{Cost of cap} = \text{R}27.16$$

The cap cost $\boxed{\text{R}27.16}$.

: Saving for a Bicycle

• Question: You want to buy a bicycle from a friend for R150, and so far you have saved R95. If you earn R16.50 an hour working at a local shop, will you earn enough extra money in three hours?

$$\text{Money needed} = \text{Bicycle cost} - \text{Money saved}$$ $$\text{Money needed} = \text{R}150.00 - \text{R}95.00$$ $$\text{Money needed} = \text{R}55.00$$

$$\text{Money earned} = \text{Hourly rate} \times \text{Number of hours}$$ $$\text{Money earned} = \text{R}16.50 \times 3$$ $$\text{Money earned} = \text{R}49.50$$

Since $\text{R}49.50 < \text{R}55.00$, you will not earn enough extra money in three hours.

No, you will $\boxed{\text{not earn enough extra money}}$ in three hours.

: Training Run Distances

• Question: In your training, you run 8.5 km on each of the first two days, then 7.95 km on the third day and 12.25 km on the fourth day. How many kilometres have you run in total?

\text{Distance (Day 1 & 2)} = 2 \times 8.5\,\text{km} \text{Distance (Day 1 & 2)} = 17.0\,\text{km}

\text{Total distance} = \text{Distance (Day 1 & 2)} + \text{Distance (Day 3)} + \text{Distance (Day 4)} $$\text{Total distance} = 17.0\,\text{km} + 7.95\,\text{km} + 12.25\,\text{km}$$ $$\text{Total distance} = 37.20\,\text{km}$$

You have run a total of $\boxed{37.20\,\text{km}}$.

: Nina's Shopping Bill

• Question: Nina brought items costing R45.78, R13.12 and R42.99. Round the final total to the nearest 5c to calculate how much she paid.

$$\text{Exact total cost} = \text{R}45.78 + \text{R}13.12 + \text{R}42.99$$ $$\text{Exact total cost} = \text{R}101.89$$

To round to the nearest 5c, we look at the last digit of the cents.
R101.89: The last digit is 9. The nearest 5c values are R101.85 and R101.90. Since 89 is closer to 90 than 85, we round up.

$$\text{Rounded total cost} = \text{R}101.90$$

Nina paid $\boxed{\text{R}101.90}$.

: Zareenah's Pencils

• Question: Zareenah bought three pencils at R1.84 each from a supermarket that rounds up totals to the nearest 5c. Calculate how much change she received from a R10 note.

$$\text{Exact cost of pencils} = 3 \times \text{R}1.84$$ $$\text{Exact cost of pencils} = \text{R}5.52$$

The supermarket rounds up totals to the nearest 5c.
R5.52: The nearest 5c values are R5.50 and R5.55. Rounding up means we go to the next higher 5c increment.

$$\text{Rounded cost of pencils} = \text{R}5.55$$

$$\text{Change} = \text{Amount paid} - \text{Rounded cost of pencils}$$ $$\text{Change} = \text{R}10.00 - \text{R}5.55$$ $$\text{Change} = \text{R}4.45$$

Zareenah received $\boxed{\text{R}4.45}$ change.