Pattie runs at 5 ft/sec
She has got a head start of 15 feet.
So after 1 second, Pattie runs = (5+15) ft
<span> = 20 </span>
ft After 2 second Pattie runs = (20+5)ft = 25 ft After 3 second Pattie runs = (25+5) ft = 30 ft After 4 seconds Pattie runs = (30+5) ft = 35 ft After 5 seconds Pattie runs = (35+5) ft = 40 ft After 6 seconds Pattie runs = (40+5) ft = 45 ft Now Keith runs at 8 ft/sec After 1 second Keith runs = 8 ft After 2 second Keith runs = (8+8) ft = 16 ft After 3 second Keith runs = (16+8) ft = 24 ft After 4 second Keith runs = (24+8) ft = 32 ft After 5 second Keith runs = (32+8) ft = 40 ft After 6 second Keith runs = (40+8) ft = 48 ft So Pattie will stay ahead of Keith upto 4 seconds. In the 5th second Pattie and Keith will be level and in the 6th second Pattie will be overtaken by Keith.