Answer: 8%
Step-by-step explanation:
The perimeter will be 2*(30+20)=2*50=100 cm
The new length will be 30+30*10/100=30+3=33 cm
The new width will be 20+20*5/100=20+1=21 cm
The new perimeter will be 2*(33+21)=2*54=108 cm
so 108=100+x*100/100
it will increase by x= (108-100)*100/100 % =8%
