Lift out of order

The lift in a tall block of flats was out of order for twelve days. The people on the fifth floor, the top one, had to use the stairs.

Lift out of order for $12$ days; the people on floor $5$ used the stairs.

Lift out of order: $12$ days, floor $5$.

Each floor has eighteen steps, so the fifth floor is ninety steps up. A step is seventeen centimetres high, so one climb lifts a person fifteen metres and thirty centimetres.

Each floor has $18$ steps: $5\times 18=90$. A step is $17$ cm: $90\times 17=1530$ cm, which is $15.3$ m a climb.

$5\times 18=90$ steps, $90\times 17=1530\text{cm}$.

One resident went out and came home three times a day. That is three climbs, or two hundred and seventy steps, which is forty-five metres and ninety centimetres of height each day.

Three climbs a day: $3\times 90=270$ steps and $3\times 15.3=45.9$ m a day.

$3\times 15.3=45.9\text{m}$ a day.

In the twelve days the same resident climbed five hundred and fifty metres and eighty centimetres in all, more than half a kilometre, just by coming home.

In $12$ days: $12\times 45.9=550.8$ m, and $550.8>500$: more than half a kilometre.

$12\times 45.9=550.8\text{m}>500\text{m}$.

After the repair, we asked ten residents. Six said they still take the stairs sometimes. Anyone with knee or heart trouble should ask a doctor before climbing a lot.

After the repair, $6$ of $10$ residents still sometimes use the stairs: $\frac{6}{10}=60\%$. With knee or heart trouble, ask a doctor first.

$\frac{6}{10}=60\%$ still climb.