I have a table as shown.

Column A Column B
Y
???? Y
???? Y
???? Y

I need a formula says if Column B = Y, then return 1 only if the sum of all
previous cells in column A is less than 25. if greater than 25, then 2. And
if all of 1 and 2 is greater than 50, then 3, and if all of 1, 2, 3 is
greater than 74, then 4.

Then I need a formula that will say, if