Let's assume
number of cookies in the beginning =x
Larry ate 1/3 Of the cookies
so, the remaining cookies are


now, we have
Barry ate 1/4 Of the remaining cookies
so, the remaining cookies are






Terry ate 1/2 Of the remaining cookies
so, the remaining cookies are



Mrs James found the tray with 6 cookies left
so, the remained cookies =6
so, we get


Hence ,
number of cookies were on the tray when Mrs James first left it on the counter are 24.............Answer