Answer:
=209.09 mg
Step-by-step explanation:
given: material= radium
half life= 1590 years
initial mass
=500mg
we know that to calculate the amount left we use
= 


therefore
= 
=209.09058407921 mg
=209.09 mg amount left after 2000 years
Answer:
60
Step-by-step explanation:
Answer:
1 and 4
Step-by-step explanation:
it's a counterexample since the product, 4 is less than the sum, 5, proving the conjecture false.
Answer:
C, D and E
Step-by-step explanation:
Given
Represent solid beads with S and clear beads with C
So:

Required
Select operations that give an equivalent ratio
First, we need to get the unit ratio

Divide through by 4
-- This means that, after any operation. The equivalent ratio must be 2: 5
Option A: Add 2 to S and 2 to C

Perform the operation


Divide through by 2

Option B: Subtract 8 from S and 6 from C

Perform the operation


Option C: Multiply S and C by 2

Perform the operation


Divide through by 8

Option D: Divide S and C by 4

Perform the operation


Option E: Multiply S and C by 18

Perform the operation


Divide through by 72


<em>From the calculations above, options C, D and E gave an equivalent of 2:5.</em>
Answer:
A.)
C.)
D.)
Step-by-step explanation:
Hope this helps:)