In Microsoft Excel 2007, which formula is used to convert the following decimal values in this particular manner?

- 1.3 should convert to 10
- 2.5 should convert to 10
- 4.8 should convert to 10
- 5.1 should convert to 10
- 7.2 should convert to 10
- 10.1 should convert to 20
- 11.4 should convert to 20
- 13.9 should convert to 20
- 17.2 should convert to 20