Answer:
Step-by-step explanation:
perimeter = 2 (l + b)
= 2 {(2/3x+ 10) + (1/3x + 5)}
= (4/3x + 10) + (2/3 + 10)
= 4/3x + 20 +2/3 + 10
= 6/3x + 30
= 3x + 30
