Frazer cycles the first 20 miles at an average speed of 21 mph. The second part is more uphill, and he only manages 13mph. By what percentage did the speed decrease

Respuesta :

Answer:

 38.1% decrease

Step-by-step 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%