Question

find the length of rectangle whose breadth is 16 cm and its perimeter is 20cm

Answer 1

P=20
B=16
20=2(l+b)
20=2(l+16)
20=2l+32
32-20=2l
12=2l
12/2=l
6=l
So length is 6cm

Answer 2

so formula of p is
2×(l+b)
so find l
p is 20
b is 16
l is= 20=2(l+ 16)
20= 2l+ 32
2l = 32- 20
2l= 12
l= 2/12
l= 6