$20\mathrm{.}10$ A closed cylindrical air$-$compressor tank is $700$ mm in diameter and is subjected to an internal pressure of $5$ MPa. The tank walls are of steel, which has an allowable tensile stress of $110$ MPa. Calculate the required wall thickness.

$($Hey$,$the book's answer is $14,950$ psi, $$I$\text{'}$d like to see how to get that by looking at your work, ~thanks$)$