Answer
$S=1804\cdot 1.04^{t}$
$5626$ cases.
Work Step by Step
We want an exponential model, $S=Ab^{t}$
At the start, April 1st, $t=0$ days, and the initial size is $A=1804$
The daily increase of $ 4\%$ is a factor of $b=1.04$
So, $S=1804\cdot 1.04^{t}$
On April 30th, the number of days passed is $t=29$
and
$S=1804\cdot 1.04^{29}\approx 5626$ cases.
