125apples were shared between jerry and kay. kay received 20% less than jerry.

If that is the case, then Jerry got 60% and Kay received 40%, because together they make the 100%, or in equations:

kay + jerry = 100%

kay = jerry - 20%

substitute:

jerry - 20% + jerry = 100%

2*jerry = 120%

jerry = 60%

kay = jerry - 20% = 60% - 20%

kay = 40%

if you want to know the amount of apples each has:

kay = 40% (125) = 0.4 (125)

jerry = 60% (125) = 0.6 (125)