Hi, both of you have explained very nicely but there is a much easier way to do this...
in 1995 let jason's salary b x so Karen is x+2000
now in 1998 both get p% increase so,
Jason= px and Karen=p(x+2000)
the diff is nw 2440 so,
p(x+2000)-px = 2440
=> px+2000p-px=2440
=>2000p=2440
=>p=1.22
and it is clear that both statements are needed to form 2 equations.