Based on the number of phones sold in 1998 and 2007, the percent increase is 500%.
The number of grams of gold used in producing the mobile devices sold in 2007 was5,400 kilograms of gold.
The mass of sold phones that were not recycled is 16,200,000 kg.
= (180 million - 30 million) / 30 million x 100%
= 500%
= 0.03 x 180 million
= 5,400,000 grams or
= 5,400 kg of gold
= 0.1 kg x 180 million x (1 - 10%)
= 16,200,000 kg
Find out more on the effects of mercury at https://brainly.com/question/8624536.