300 miles / 6 hours = 50 miles per hour
Answer:
The correct answer is "22.27 hours".
Explanation:
Given that:
Radioactive isotope activity,
= 490,000 Bq
Activity,
= 110,000 Bq
Time,
= 48 hours
As we know,
⇒ 
or,
⇒ 
By taking "ln", we get
⇒ 
By substituting the values, we get
⇒ 
⇒ 

As,
⇒ 
then,
⇒ 
⇒ 