Type a value in a cell based on another cell

Hello,
i need to make vba to do that
if ("A1") between 1 , 2 than ("B1")= 15
else if ("A1") between 2 , 3 than ("B1")= 10
else if ("A1") between 3 , 4 than ("B1")= 5
Thus, with other cells
A2 B2
A3 B2
A4 B2