If your hair is brown, purple probably isn't going to show up very well. It's best to bleach your hair before dying it an unnatural color. Like I told you before, the box says 30-40 minutes, but the most I'd leave it on for is an hour. And that's at your own judgment, too.
But China's population statistics can be particularly misleading. Virtually overnight, Chongqing has become the largest city not only in China, but in the world, Time Magazine proclaimed in 2005. But it wasn't true-Chongqing is not the largest city in the world, or even in China.
The largest metropolitan area by population is Tokyo, at approximately 32 million. The largest city by population is Mumbai, at approximately 13 million. The largest city by area is Hulun Buir, China, with an area of approximately 264,000 square kilometers (roughly the size of Colorado). However, most of this city is undeveloped. The largest metropolitan area by area is New York, with an area of approximately 9000 square kilometers.