Hiu
How I can solve this question
To graph the equation between 0 and 5 start with the ordered point (0,100)
You know that in 1 hour the amount will be $\displaystyle 2^2 = 4$ times the amount at 0 so you get the second ordered pair of (1,400)
Plot the others similarly and draw the graph
Spoiler:
As the graph is exponential growth I suggest using a log scale on the y axis
$\displaystyle ln(y) = kt + ln(A_0)$ which gives a straight line in the form $\displaystyle y=mx+c$
Edit: Plot $\displaystyle ln(y)$ against $\displaystyle t$ to get the straight line, with gradient $\displaystyle k$ and y intercept $\displaystyle ln(A_0)$