Yes; his answer is correct.
John can do this by multiple ways, but most likely he just remembered this one. Here are some ways.
1. He used his fingers; he put 1 finger, then another finger, and got 2 fingers up. The answer is 2.
2. He remembered it; usually Kindergarteners learn this and this is very easy to remember.
3. He used the things around him; I have 1 crayon then add another, how many do I have? 2.
0.584 is greater than 0.58 !
A half of 4 is 2 because 2+2=4
Answer:
Next will be 33, 25, and 21
Step-by-step explanation:
For the half-life of a certain substance, the equation that would best represent the scenario is,
At = Ao(0.5^t/n)
where At is the amount at any time t, Ao is the original amount, and n is half-life. Substituting the known values,
At = (220 mg)(0.5^(396/72)
At = 4.86 mg
Thus, after 396 days, there will only be 4.86 mg of Terbium-160.
