Two trains started at $7 \mathrm{AM}$ from the same point. The first train travelled north at a speed of $80 \mathrm{~km} / \mathrm{h}$ and the second train travelled south at a speed of $100 \mathrm{~km} / \mathrm{h}$. The time at which they were $540 \mathrm{~km}$ apart is _____________AM.

(A) 9

(B) 10

(C) 11

(D) 11.30

Two trains started at $7 \mathrm{AM}$ from the same point. The first train travelled north at a speed of $80 \mathrm{~km} / \mathrm{h}$ and the second train travelled south at a speed of $100 \mathrm{~km} / \mathrm{h}$. The time at which they were $540 \mathrm{~km}$ apart is _____________AM.

(A) 9

(B) 10

(C) 11

(D) 11.30

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