The first thing you should know is that the rate of each one is:
Kaitlyn = 1/6
Mark = 1/8
Then,
d = number of days.
The equation then if they work together is:
1 / 6d + 1 / 8d = 1
answer:
the equation for number of days it would take to build the sheld together is
1 / 6d + 1 / 8d = 1