A farmer wishes to start a 100 square metres rectangular vegetable garden. Since he has only 30 m barbed wire, he fences three sides of the garden letting his house compound wall act as the fourth side fencing. The dimension of the garden is:  Pick:
A) 15 m × 6.67 m	B) 20 m × 5 m	C) 30 m × 3.33 m	D) 40 m × 2.5 m	E) None of these
We have : 2b + l = 30 ⇒ l = 30 – 2b.   Area = 100 m2 ⇒ l × b = 100 ⇒ b(30 – 2b) = 100   ⇒ b2 – 15b + 50 = 0 ⇒ (b – 10)(b – 5) = 0   ⇒ b = 10 or b = 5.   When b = 10, l = 10 and when b = 5, l = 20.   Since the garden is rectangular,   so its dimension is 20 m × 5 m.   Answer 20 m × 5 m
<result>B</result>
A farmer wishes to start a 100 square metres rectangular vegetable garden. Since he has only 30 m barbed wire, he fences three sides of the garden letting his house compound wall act as the fourth side fencing. The dimension of the garden is: