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 )
Answer:
7(6m - 4) = -364
multiply 7 for both variables in the parenthesis
42m - 28 = -364
move 28 to other side
42m= -336
divide 42 on both sides
m= -8
Answer:
that other person is right
The answers is 3/9 which you can check by reducing. It reduces to 1/3. Basically you go 1/3 = x/9 then cross multiple to get 9=3x do the division so 3x/3 and 9/3 and you get 3/9.
48 inches to 30 inches is a decrease.
percent decrease = change/original value x 100%
= (48 - 30)/48 x 100%
= 18/48 x 100%
= 37.5% decrease
