I am hoping that I have come to the right place for a push in the right direction. I have got the following question and I think I know the equation but when I put the values in it doesnt seem to give the correct answer, the equation I have are

long= pd/4tnh

hor= pd/2tnl

A thin cylinder compressed air vessel has an internal diameter of 1,5m and is made of plate 10mm thick. The joint efficency of the longitudinal joint is 75% and the circumferential joint 50%. The plate has a tensile strength of 400MPa. What is the maximum internal pressure to which the vessel should be used if there is to be a factor of safety of 5?

Any help welcome

Thanks

Anna