3180 because you divide 31800 by 10
You can draw two quarters, a dime, a nickel, and three pennies. Or 6 dimes and 8 pennies.
The function for the amount saved if they purchase a used drone rather than a new drone from Jim's store is f(x) = 0.45x
He sells used drones at 70% of the price (x).
So, the selling price of a used drone is:

Express percentage as decimal


Also, he sells new drones at 15% more of the price (x).
So, the selling price of a new drone is:

Express percentage as decimal



The amount saved is the difference between the prices of the drones.
So, we have:

This gives

Subtract

Express as a function

Hence, the function for the amount saved is f(x) = 0.45x
Read more about proportions at:
brainly.com/question/13114933
If you mean hours, and Minutes that is 1 hour and 30 minutes.. s a fraction that is 1 1/2. Or 90/60