It would be great if someone could answer this :)

Step-by-step explanation:

You could do this step by step.

The first year is left alone: 90,000 kt

The second year is 90000 * 0.96 That represents a 4% reduction

Second year = 86400

Third year = 86400 * .96 = 82944

Fourth year = 82944 * 0.96 = 79626.24 Here's where you run into your first dilemma. What do you do with that 0.24? The answer is, you round it here, but leave it in your calculator.

Fourth year = 79626

Fifth year = 79626.24 * 0.96

Fifth year = 76441

Sixth year = 79626.1904 * 0.96

Sixth year = 73383.542

Sixth year = 73384

Of course once you have gone through all that, you could do it this way

Sixth year = 90000 * 0.96^(n - 1) = 73383.54 = 73384

Same answer both ways.

I'm going to leave the addition to you.

Sum = a* (r^(n) - 1)/ (r - 1)

Sum = 90000 * (0.96^5 - 1) / (0.96 - 1 ) = 415411 rounded. I think that's right, but check it out.

18a

step-by-step explanation:

simply because it is. it's the highest common factor

true !

step-by-step explanation: