Question

3 With 72 million bicycles, correct to the

nearest million, Japan is at the top of the list
of countries with most bicycles per person.
On average, Japanese people travel about
2 km by bicycle, correct to the nearest km,
each day. Calculate the upper bound for the
total distance travelled by all the bicycles in
Japan.

Answer 1

181 million km

Explanation:

"Correct to the nearest unit" means the actual value might be 1/2 unit larger (or smaller) than the reported value.

The upper bound would be the product of the maximum number of bicycles and the maximum distance each travels:

(72.5 · 10^6 bicycles)(2.5 km/bicycle) = 181.25 · 10^6 km

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Since the given numbers are good to 2 significant figures (or so), we might reasonably put the upper bound as 180·10^6 km.