I'm pretty sure it is 25. A method you could use(calculator would be more quicker, but by hand works too) is dividing 15 by sixty percent. To do that, u find the decimal of sixty percent. You would move the decimal point of sixty(the original place of the decimal would be 60.0) two places to the left. Then 60% would become 0.60. But, you could simplify that to 0.6, then you do 15 divided 0.6. You would get 25. If you are doing it by hand, double check the answer by multiplying it with the decimal and you should get the original number(which is 15 in this case). I hope this helped :)
