How long does it take Llya to cover the distance of 5.00 miles and what is her average speed?

Ilya and Anya each can run at a speed of 8.50 mph and walk at a speed of 3.50 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half.

Her time averaged speed is (8.50+3.50)/2=6 mph. This would mean it would take her 5/6= 50 minutes to finish the track. Of this she will run 25 minutes thus covering a distance of 8.5*2.5/6=3,54 mile running and 3.5*2.5/6=1,46 mile walking (which adds up to 5 as it should be). Her distance averaged speed would therefore be (3.54*8.5+1.46*3.5)/5= approximately 7 mph.

(Ilya will be faster since she is running a mile more than Anya)

How long does it take anya to cover the distance of 5.00 miles ?