To find 2 percent of 7.8 billion, you first convert 2 percent into a decimal. This is done by dividing 2 by 100, which gives you 0.02.
Next, you multiply 0.02 by 7.8 billion:
0.02 x 7,800,000,000 = 156,000,000.
So, 2 percent of 7.8 billion is 156 million.