Given :-
- The perimeter of a rectangle is 42 inches.
- The width of the rectangle is 6 inches.
To Find :-
Solution :-
We know that,
☆ Perimeter of a Rectangle = 2 (length + width)
Hence,
42 = 2 (length + 6)
or, 42/2 = length + 6
or, 21 = length + 6
or, length = 21 - 6
or, length = 15
The length is 15 inches.
Therefore, the correct answer is option (B) 15 inches.