Question

The half-life of radium is 1690 years. If 80 grams are present now, how much will be present in 210 years?

Answer 1

75.03

Explanation:

1690 40

210 x

1690x = 210 * 40

x = (210 * 40)/ 1690

x = 4.97041420118

80 - 4.97 = 75.03