Answer: 30cm

Step-by-step explanation: Length = 10 cm

width = 5 cm

perimeter= 30 cm

Step-by-step explanation:

perimeter of a rectangle= p= 2*L +2*w

L= length

w= width

area of a rectangle=A= L*w

the statement tell us:

L= 5+w

A = 50cm^2

so we have:

50 = (5+w)*w

50=5w+w^2

we have :

w^2 +5w-50=0

we apply the quadratic formula

a=1    b=5  c=-50

so width= (-5+15)/2

width=5cm

L= 5+w=5+5=10 cm =length

perimeter=2(10)+2*(5)=20+10=30 cm