Answer:
60
Step-by-step explanation:
let x be the chocolates in a gift box
David took = 40/100*x
Left by David: x-40/100*x = 60/100*x
Now Eric took: 25/100*(60/100*x)
David + Eric = 40/100*x+25/100*(60/100*x) = 55x/100
Now x-55x/100 = 45/100x = Left over = 27
45/100x = 27
x = 27*100/45 = 3*100/5 = 3*20 = 60