Diego changed 200 euros to Argentine Peso. The exchange rate was 1 euro - 24.8 pesos. Work out how many pesos he received.

Diego received $\boxed{\text{4960 pesos}}$.

4. (c) The distance between Madrid and Buenos Aires is 10 050 km. Diego's return flight took 12 hours and 30 minutes. Calculate the average speed, in km/h, for the return flight.

The average speed is $\boxed{\text{804 km/h}}$.

5. Find the highest odd number that is a factor of both 60 and 90.

Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60

Factors of 90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90

Common factors: 1, 2, 3, 5, 6, 10, 15, 30

Odd common factors: 1, 3, 5, 15
The highest odd number that is a factor of both 60 and 90 is $\boxed{15}$.

6. Put in one pair of brackets in each statement to make it correct.

6. (a) $16 + (8 + 4 \times 2) = 1$
To get 1, we need the expression to evaluate to $16 - 15$.
Let's try placing brackets to make the part after 16 equal to -15. This is not possible with addition.
Let's re-examine the problem. It's $16 \div (8 + 4 \times 2) = 1$. Assuming the operation is division, not addition, to make the result 1.
If it's $16 \div (8 + 4 \times 2) = 1$:

So, the brackets should be: $\boxed{16 \div (8 + 4 \times 2) = 1}$.
Self-correction: The image clearly shows a plus sign, not a division sign. Let's re-evaluate with the plus sign.
If the equation is $16 + (8 + 4 \times 2) = 1$, this is impossible to make true by just adding one pair of brackets, as $16 + (\text{positive number})$ will always be greater than 16.
However, if the question implies that the operation itself might be missing or incorrect, and we are meant to insert brackets to make it true, it's ambiguous.
Given the context of typical math problems, it's highly probable that the operation shown is incorrect or there's a typo in the question. If we assume the operation is division, the solution above works.
If we strictly stick to the plus sign, no single pair of brackets will make $16 + (\text{something})$ equal to 1.
Let's assume there's a typo and it should be $16 - (8 + 4 \times 2) = 1$ or $16 \div (8 + 4 \times 2) = 1$.
Given the student's previous work, they might be expecting a division or subtraction.
If it's $16 - (8 + 4 \times 2) = 1$:
$16 - (8 + 8) = 1$
$16 - 16 = 0 \neq 1$.
If it's $16 \div (8 + 4 \times 2) = 1$:
$16 \div (8 + 8) = 1$
$16 \div 16 = 1$. This works.

Let's assume the operation is division, as it's the most common way to get 1 from 16 and another number.
$\boxed{16 \div (8 + 4 \times 2) = 1}$

6. (b) $16 + (8 + 4 \times 2) = 12$
We need the expression to evaluate to $16 - 4 = 12$. So, the part in brackets should result in $-4$. This is not possible with the given numbers and operations.
Let's try to make the part in brackets equal to $-4$.
If we assume the operation is subtraction: $16 - (8 + 4) \times 2 = 12$
$16 - (12) \times 2 = 12$
$16 - 24 = -8 \neq 12$.
If we assume the operation is subtraction: $16 - (8 + 4 \times 2) = 12$
$16 - (8 + 8) = 12$
$16 - 16 = 0 \neq 12$.

Let's consider if the brackets change the order of operations to make the result 12.
Original expression without brackets: $16 + 8 + 4 \times 2 = 16 + 8 + 8 = 32$.
We need to reduce this to 12.
Try $(16 + 8) + 4 \times 2 = 24 + 8 = 32$.
Try $16 + (8 + 4) \times 2 = 16 + 12 \times 2 = 16 + 24 = 40$.
Try $16 + 8 + (4 \times 2) = 16 + 8 + 8 = 32$.
It seems there might be a typo in the question or the operation.
If the operation was subtraction, for example: $16 - (8 + 4) = 12$
$16 - 12 = 4 \neq 12$.
If it was $16 - (8 - 4) \times 2 = 12$
$16 - (4) \times 2 = 12$
$16 - 8 = 8 \neq 12$.

Let's assume the question intends for the brackets to be placed such that the expression evaluates to 12.
If the operation is $16 - (8 + 4) \div 2 = 12$:
$16 - 12 \div 2 = 12$
$16 - 6 = 10 \neq 12$.

Given the exact wording "Put in one pair of brackets in each statement to make it correct", and the presence of a plus sign, it's highly likely there's a typo in the question itself, as $16 + (\text{positive number})$ cannot equal 12.
However, if we consider the possibility of a division sign instead of a plus sign, similar to part (a):
If it's $16 \div (8 - 4) \times 2 = 12$:
$16 \div 4 \times 2 = 12$
$4 \times 2 = 8 \neq 12$.

Let's assume the question is $16 - (8 - 4 \times 2) = 12$.
$16 - (8 - 8) = 12$
$16 - 0 = 16 \neq 12$.

Let's try to make the expression $16 + (\text{something})$ equal to 12. This means the "something" must be $-4$.
This is not possible with $8, 4, 2$ and multiplication/addition.
There must be a typo in the question. If we assume the operation is subtraction, for example:
$16 - (8 - 4) \times 2 = 12$
$16 - (4) \times 2 = 12$
$16 - 8 = 8 \neq 12$.

Let's consider if the question meant $16 - (8 + 4) + 2 = 12$.
$16 - 12 + 2 = 4 + 2 = 6 \neq 12$.

Given the constraints, and the high probability of a typo in the question, I cannot provide a solution that strictly adheres to "one pair of brackets" and the given operations to reach 12.
If we assume the question meant $16 - (8 - 4) \times 2 = 12$, it doesn't work.
If we assume the question meant $16 - (8 + 4) \div 2 = 12$, it doesn't work.

Let's assume the question meant to be $16 - (8 - 4) \times 2 = 12$ but the numbers are slightly different.
If the question was $16 - (8 - 2) \times 2 = 12$:
$16 - (6) \times 2 = 12$
$16 - 12 = 4 \neq 12$.

I will state that this question appears to have a typo, as it's not possible to achieve 12 with the given numbers and operations using only one pair of brackets and the addition sign.
However, if we consider a common type of problem where the operation might be different, for example, if it was $16 - (8 - 4 \times 2) = 12$:
$16 - (8 - 8) = 12$
$16 - 0 = 16 \neq 12$.

Let's try to make the expression $16 + (\text{something})$ equal to 12. This means the "something" must be $-4$.
This is not possible with $8, 4, 2$ and multiplication/addition.
I will provide the most plausible interpretation if a typo is assumed.
If the question was $16 - (8 - 4) \times 2 = 12$, it would be $16 - (4) \times 2 = 16 - 8 = 8$.
If the question was $16 - (8 + 4) + 2 = 12$, it would be $16 - 12 + 2 = 6$.

Given the ambiguity, I will state that the problem as written with a '+' sign cannot be solved by adding one pair of brackets. If there was a typo and it was $16 - (8 + 4) = 12$, then $16 - 12 = 4 \neq 12$.
If it was $16 - (8 - 4) = 12$, then $16 - 4 = 12$. This would work if the operations were different.
Assuming the operations are fixed, and only brackets can be added:
$16 + (8 + 4 \times 2) = 16 + (8 + 8) = 16 + 16 = 32 \neq 12$.
$16 + (8 + 4) \times 2 = 16 + 12 \times 2 = 16 + 24 = 40 \neq 12$.
$16 + 8 + (4 \times 2) = 16 + 8 + 8 = 32 \neq 12$.
It is not possible to make this statement correct with the given operations and numbers by adding one pair of brackets. There is likely a typo in the question.

7. (a) Write the number 0.0605 in standard form.

To get 6.05, the decimal point needs to move 2 places to the right.

Since the decimal point moved 2 places to the right, the exponent will be $-2$.

The number in standard form is $\boxed{6.05 \times 10^{-2}}$.

7. (b) Calculate $(1.63 \times 10^{12}) \times (2.47 \times 10^{-4})$. Give your answer in standard form.

The numerical part 4.0201 is already between 1 and 10, so no further adjustment is needed.
The answer in standard form is $\boxed{4.0201 \times 10^8}$.