IBHardNumber7–9

Bounds on an Average Speed

Limites da Velocidade Média

A runner covers a track measured as $400$ m to the nearest metre, in a time measured as $52.4$ s to the nearest tenth of a second. Find the smallest and the largest possible average speed, in metres per second, each to $3$ significant figures.

Each measurement stands for an interval, not a single number, so write both intervals down first. Then think about which end of each interval makes the quotient largest, remembering that a larger denominator makes a quotient smaller.

Solution

Step 1 of 10

1.The distance is measured to the nearest metre, so it lies in