50% of what number is 65?

Alake near the arctic circle is covered by a sheet of ice during the cold winter months. when spring arrives, the ice starts to melt. s(t) models the ice sheet's thickness (in meters) as a function of time tt (in weeks). s(t)=-0.25t+4

Use set buikder notation to represent the following set: {, -2, -1, 0}

If the segment op is dilated by a scale factor r=2, what is the length of segment op? a)10cm b)16cm c)6cm d)4cm