Air pressure and force of lift

[spidey64]

I know about Bernoulli's principle and that a difference of pressure below and above a wing create lift, but I cannot find anywhere a formula or any information on how to find the amount of lift given the surface area of the wing and the difference in pressure as a percentage of atmospheric pressure...my book is not helpful at all.

 

[spidey64]

I've found that force = area X pressure, which of course makes sense...but given that my problem gives me the difference of pressures below and above as 4% atmospheric pressure, is the pressure value in that formula .04?