We know that the stock value doubles every 42 days and that the stocks start out with $5.00.
We should find the value of the stock in 18 weeks. Let us denote this value with S.
One week has 7 days, so 18 weeks have: 18*7=126 days.
In order to find how many times the stocks value was doubled we should divide this number of days with 42: 126/42=3
So, after 18 weeks the value of the stock would be: 5->5*2->(5*2)*2=40
answer:
D.)$40.00