Question

6) Frazer cycles the first 20 miles at an average speed of 21mph. The second

part is more uphill, and he only manages 13mph. By what percentage did his
speed decrease?
How to solve

Answer 1

9514 1404 393

Answer:

38.1% decrease

Explanation:

A percentage change is found from ...

% change = (change)/(original amount) × 100%

= (new value - original amount)/(original amount) × 100%

= (13 -21)/21 × 100% = -8/21 × 100% ≈ -38.1%

Frazer's speed decreased by 38.1% during the second part.

_____

Additional comment

A negative % change represents a decrease; a positive % change represents an increase.