Question 8
A certain pen can draw a line $0.4$ mm wide and $1$ km long before it runs out of ink. The largest square you can colour in with this pen has an area, in square metres, of
(A) $4\,000$ (B) $400$ (C) $40$ (D) $4$ (E) $0.4$
(A) $4\,000$ (B) $400$ (C) $40$ (D) $4$ (E) $0.4$