Can someone help me with this?

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents

Sketch the vector field vector f( vector r ) = 8vector r in the xy-plane. select all that apply. the length of each vector is 8. the lengths of the vectors decrease as you move away from the origin. all the vectors point away from the origin. all the vectors point in the same direction. all the vectors point towards the origin. the lengths of the vectors increase as you move away from the origin.

Asalesperson has january sales of $20,000(1,$20,000) and april sales of $80,000 (4,$80,000). what is the rate of change?