Motoring costs may be claimed at the following rate:
First 10000 miles at 40p per mile
Mileage over 10000 at 25p per mile
Return the amount that may be claimed for the specified milage.
If the mileage is more than 10000 we can use the following expression:
10000*0.40 + (miles-10000)*0.25
The claimant gets 10000*0.40 for the first 10000 miles then
miles-10000 is the mileage in excess of 100000.