Explanation:
Given that,
Runner 1 runs 14 miles in 3 hours. His average speed is given by :
[tex]v_1=\dfrac{14\ miles}{3\ h}=4.67\ mph[/tex]
Runner 2 runs 16 miles in 4 hours. His average speed is given by :
[tex]v_2=\dfrac{16\ miles}{4\ h}=4\ mph[/tex]
Runner 3 runs 15 miles in 6 hours. His average speed is given by :
[tex]v_3=\dfrac{15\ miles}{6\ h}=2.5\ mph[/tex]
Total distance covered by all three runners, D = 14 + 16 +15 = 45 miles
Total time taken, t = 3 + 4 + 6 = 13 hours
The average speed of all the runners together is given by :
[tex]V=\dfrac{45\ miles}{13\ h}\\\\V=3.46\ mph[/tex]
Hence, this is the required solution.
