Try this...
1. Start a new spreadsheet
2. In cell A1 type the flight duration 00:48
3. In cell A2 type the hire rate (ex VAT) £150
4. In cell A3 type the formula =A1*24*B1*1.175
5. Change format of cell A3 to be Currency (example answer should be £141.00)
That should get you on your way?
RC