Question

)A train travels at a constant speed of 800 mph and covers distance of 2660 miles another distance it covers is 208 miles at a constant speed of 624 mph. What was it’s average speed for a trip?

Answer 1

$u_1=800\ mph \\ d_1=2660\ miles \\ t_1= \frac{d_1}{u_1}= \frac{2660}{800} =3.325\ h\\ \\u_2=624\ mph \\ d_2=208\ miles \\ t_2= \frac{d_2}{u_2}= \frac{208}{624} =0.333\ h\\ \\total\ distance(d)=d_1+d_2=2660+208=2868\ miles\\total\ time(t)=t_1+t_2=3.325+0.333=3.658\ h\\ \\average\ speed= \frac{d}{t}= \frac{2868}{3.658}=\boxed{784\ mph}$