If the length and breadth of a rectangular room are each increased by 1 m, then the area of floor is increased by 21 sq. m. If the length is creased by 1 m and breadth is decreased by 1m, then the area is decreased by 5 sq. m. The perimeter of the floor is: Pick:
A) 27
B) 35
C) 40
D) 49
E) 38
Let length = x meters and breadth = y meters.   Then,   (x + 1) (y + 1) - xy = 21   x + y = 20 Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦1   And, xy - [(x + 1) (y - 1)] = 5   x - y = 6 Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦Ã¢â‚¬Â¦..2   Solving (i) and (ii), we get : x = 13 and y = 7   So, length = 13 m and breadth = 7 m.   Perimeter = [2 (13 + 7)] m = 40 m.   answer : 40
<result>C</result>
If the length and breadth of a rectangular room are each increased by 1 m, then the area of floor is increased by 21 sq. m. If the length is creased by 1 m and breadth is decreased by 1m, then the area is decreased by 5 sq. m. The perimeter of the floor is: