Hard to say exactly how long it took her, but if you're just approximating it's not the hardest:
70 x 385
70 x 400 - 70 x 15
28,000 - 70 x 10 - 70 x 5
28,000 - 700 - 350
28,000 - ~1,000
27,000 cm
270 m
plus she has her phone out so maybe she was just lazy and calculator app'd it lol.