1.5.
Three halves is one and a half, or 1.5 when written as a decimal.
1.5
1.5
19 halves as a decimal is 9.5.
2.0 is the decimal of four halves
3.5
2.5
2.0
1.5
3
There are seven halves in three and a half. This is because three whole units contain six halves, and adding the half gives a total of seven halves.
Three halves or 1.5 as a percent would be 150%.