Question 102731
Let p=original perimeter P+30=new perimeter
{{{(p+30)/p=5/4}}}
4(p+30)=5p multiply both sides times 4p to eliminate fractions.
4p+120=5p 
p=120 subtract 4p from both sides.
p+30=150
Check:
{{{150/120=5/4}}}
Ed