Cobalt 60 has an annual decay rate of 13% how many grams of a 300 g sample one will remain after 20 years round the answer to two decimal places

18.51 grams.

Step-by-step explanation:

We have been given the decay rate

We have general equation for decay which is:

;

Here, we are given with initial sample which is a=300

b=1-13%

And t is 20 years.

We will subatitute the values in the formula we get:

After simplification we get y=18.51 grams.

The sample remain will be 18.51 grams.

the answer is 13

step-by-step explanation:

5*5=25

12*12=144

25+144=169

169^2=13