Meg would be a to be correct
The Greatest Common Factor (GCF) of 25, 5, 11 and 23, 52, 7 is 1, same with 22,3 and 23, 5 and 13, 193, 232.
A half-life of the isotope is 15 days and at start its mass is 32 g.
A table:
t: m:
0 32 g
15 16 g
30 8 g
45 4 g
60 2 g
75 1 g
In the first column is used an arithmetic sequence ( a 1 = 0, d = 15 ).
In the second column is used a geometric sequence ( a 1 = 32, r = 1/2 )
16x^2=9
x^2=9/18
x=sqrt(9/16)
x=3/4,-3/4
so the root of the quadratic equation are 3/4 and -3/4
