Question

A person walked 1.5 miles in 28 minutes and then jogged 1.2 more miles in 10 minutes. What was the average speed in miles per minute?

Answer 1

`s=(d)/(t),\ where\ s-speed,\ d-distance,\ t-time\\\\s_1=(1.5)/(28)=(15)/(280)=(3)/(56)\\\\s_2=(1.2)/(10)=(12)/(100)=(3)/(25)\\\\s_a=((3)/(56)+(3)/(25))/(2)=((75)/(1400)+(168)/(1400))/(2)=(243)/(1400)\cdot(1)/(2)=(243)/(2800)(miles)/(minute)`