The breath of a rectangular landscape is 6 times its length. There is a playground in it whose area is 4200 square mtr & which is 1/7 th of the total landscape. What is the breath of the landscape?  Choose the correct choice from the following options:
A) 520
B) 420
C) 320
D) 550
E) 450

Rationale: "sol . 6 x * x = 7 * 4200 x = 70 length = 6 * 70 = 420 b"
Answer: B