Answer:
27.76 grams will be present in 500 years
Step-by-step explanation:
The given formula is
, where A is the value of the substance in t years, and
is the initial value
∵ The half-life is a substance is 375 years
- Substitute A by
and t by 375 to find the value of k
∴ 
- Divide both sides by
∴ 
- Insert ㏑ in both sides
∴ ㏑(
) = ㏑ (
)
- Remember ㏑ (
) = n
∵ ㏑ (
) = 375 k
∴ ㏑(
) = 375 k
- Divide both sides by 375
∴ k ≈ -0.00185
∴ 
∵ 70 grams is present now
- That means the initial value is 70 grams
∴
= 70
∵ The time is 500 years
∴ t = 500
- Substitute the values of
and t in the formula
∵ 
∴ A = 27.76
∴ 27.76 grams will be present in 500 years