Question 388208
Shift the words around:
"$6 of what amount of money is 15% ?" 

Let y be the amount of money you want to find.

{{{6/y = 15/100}}} remember a percent always goes over 100.

Multiply each side by y, because we want to find y and its in the denominator right now, and that's not good.

{{{(y)*(6/y) = (y)*15/100}}}  Left side y cancels out.
{{{6 = 15y/100}}}  Multiply each side by 100 to get rid of fraction on right.
{{{(100)*6 = (100)*(15y)/100}}}  Right side 100 cancels out.
{{{600 = 15y}}}  Now solve for y : divide each side by 15.
{{{600/15 = 15y/15}}}
{{{40 = y}}}  

$40 is the total amount of money. Eyeball this answer. Does it seem right?
Does $6 sound like 15% of $40?  
What is close to 15% Try 10%. What is 10% of 40? $4. That's close to $6.