Question

find the width of a rectangle with a perimeter of 90 M and length of 15 m

Answer 1

perimeter of rectangle = 2(l+b)
                                90 =2(15+b)
                                90/2=15+b
                                45=15+b
                                45-15=b
                                   30 = b

the width is 30 m.

Answer 2

Let the breadth or width of recatangle be x
Length = 15m
Perimeter = 90m
=> 2 ( l+b ) = 90m
=> 2 ( 15 +x ) = 90m
=> 30 + 2x = 90m
=> 2x = 90 - 30
=> 2x = 60
=> x = 60 / 2
=> x = 30m
The breadth of rectangle is 30m.