How do you solve this?and explain.

Amount = A = $50(1 + 0.03/12)^(12*m), where m is the # of months.  Note that A= $50 at the beginning (when m=0).  Note that I am assuming that "3%" is ANNUAL interest.  

If, on the other hand, "3%" is monthly (very unlikely!!), then:

Amount = A = $50(1 + 0.03)^(m)

Ucan draw that on a graph sheet and count the no. of units and apply the area formula of rectangle