The question is incomplete, here is the complete question:
Recall that m(t) = m.(1/2)^t/h for radioactive decay, where h is the half-life. Suppose that a 500 g sample of phosphorus-32 decays to 356 g over 7 days. Calculate the half life of the sample.
<u>Answer:</u> The half life of the sample of phosphorus-32 is 
<u>Step-by-step explanation:</u>
The equation used to calculate the half life of the sample is given as:

where,
m(t) = amount of sample after time 't' = 356 g
= initial amount of the sample = 500 g
t = time period = 7 days
h = half life of the sample = ?
Putting values in above equation, we get:

Hence, the half life of the sample of phosphorus-32 is 
Answer:
Hello,
I am pretty sure that is is the last answer. 3√3.
Step-by-step explanation:
I hope this helps!
The third option is the right one
There are a total of 900 students at Molly’s school. 810 is 90% of 900. 90% of students did not wear a silly hat.
Answer: 78
Step-by-step explanation:
just add the time all together then this will be your answer.