Answer
a) 25 seconds
b) Yes
Work Step by Step
a)
$7.5(x+1)=7.8x$
$7.5x+7.5 = 7.8x$
$7.5x+7.5-7.5x=7.8x-7.5x$
$7.5 = .3x$
$7.5/.3 = .3x/.3$
$25 = x$
b)
At 25 seconds, both Michelle and Pam will have covered 195 meters. Pam is .3m/s faster than Michelle, so Pam will pass Michelle at the 25 second mark. Michelle will take 2/3 of a second to cover the last five meters, and Pam will take less than 2/3 of a second to cover the last five meters.