3 halves times the product of 3 1 fifth

 48/10 , if you need it simpflity then its 4 and four fifths ( 4 4/5 )    

She would ride 17,343.75 kilometers in three days because the first day is 7,500 meters and the get the third day you multiply that by .75 which would be 5,625, and to get the third day you would multiply the 5,625 by .75 to get about 4,218. Lastly, you would add the three numbers together