Example $8\mathrm{.}7$: A particular soil failed under a major principal stress of $300k\frac{N}{m^2}$ with a

corresponding minor principal stress of $100k\frac{N}{m^2}.$ If$,$ for the same soil, the minor principal

stress had been $200k\frac{N}{m^2},$ determine what the major principal stress would have been if

$($a$)=30$ and $($b$)=0.$