Can someoneme. really important
1. find the time required for an investment of $5000 to double at an annual rate 7.5% compounded quarterly. round your answer to the whole year.
2. the half-life of radium-226 is 1600 years.
a) what is the exponential decay rate? round to 5 decimal place.
b) suppose we have 22mg sample. how much of the sample will remain after 4000 years. round to two decimal places
explain step by step.

1. so 5000
so in the first quarter 5000 + (5000 times 0.075)=5375
second quarter 5375+(5375 times 0.075)=5.778.13
third quarter 5.778.125+(5778.125 times 0.075)=6211.48
and so on
when you get to 2.5 years you get 10305.2 which is more than double but round answer to whole year so
3 years you get 11908.9

2. a half life is how long it takes for half of the sample to decay so
a. not sure how to do this sorry.
b. so  there are 2.5 1600s n 4000 so (22 times 1/2)=11 then 11 times 1/2=5.5 then since only half of the half life has passed then only 1/4 has passed away so
5.5-(5.5 times 1/4)=4.125
after 4000 years there will be 4.13 grams

We’re gonna need a picture to refer to in order to figure it out. try reposting your question with the picture included.