Hi Aris,

Here's a simple proportion that you can use to solve your question:

amount of change = r  

original number       100

where r is the rate of change or the percent. In your case, that rate would be 60%. You will also need to know the "original number." Let's pretend, for our discussion that this number happens to be 350 (a random number).  Then the equation would look like this:

x/350 = 60/100

When we cross multiply, we get: 100x = 21,000. We then divide both sides by 100 to eliminate the coefficient from the variable "x". The resulting answer is: 210.

What does this means? This means that the rate of change of 60% for 350 is 210.

I hope this helps you!