Answer:
200 kg
Step-by-step explanation:
First hour he sold 15% <em>(remaining is 85%)</em>
Second hour he sold 20% of remaining <em>(which is 85%)</em> -- so he sold
, which is 17% (remaining 85-17=68%)
Third hour he sold 25% of remaining <em>(which is 68%)</em> -- so he sold
, which is 17%
In third hour he sold 34, so 17% is 34. To find total he initially had, we need to find (100%). We can setup the ratio (letting x equal his initial amount):

Initially the farm stand owner had 200 kg of apples.
Drag the decimal any number n towards the right and divide by 10^n