Maths week 2 term 3

Hi, this week for maths, we had to do maths on our new bike track. 

Here's the qustions  we can chooses from

1. Using the image above, what is the ratio between the pedal gear and sprocket?

If you were to turn the crank 9 full rotations how many revolutions would the wheel do?

If one rotation of the pedal gear moves the bike 150cm, how far will the bike travel around the track if you did 5 full rotations of the pedal gear.

Which gear ratio would you have to pedal more as you go once around the bike track - 4:1 or 2:1, what is your reasoning?

2.There are currently three big tree stumps sitting in the way of where the bike track will go.

The stump removal company have quoted $253 to get the three tree stumps removed.

They are currently running a special of 20% off stump removal for the next week. If we book in during this time…

 What would the dollar amount of our discount be? 

What would the total price now be to get the 3 stumps removed?

Now that we have calculated the price of removal, the company have made contact and said we can have a further 17% off if we pay in advance, what will the cost now be, if we take up their offer?

I chooses number 2, Here's my work.

How would you work it out?

Do you get how I worked it out?

Can you answer both of the qustions?