Answer:
Step-by-step explanation:
Let's solve this using our formula for exponential functions:
where a is the initial value and b is the growth/decay rate. We will fill that equation in with 2 of the coordinates on the graph and come up with the values for both a and b. (0, 3) and (1, 6):
. Anything raised to the power of 0 is 1, so that means that
a = 3. We will use that value along with the x and y from the second coordinate to solve for b:
. b to the first is just b, so our equation is
6 = 3b and
b = 2.
Our equation then is
, the third choice down.
We know that 172 of them were wood, so the rest are metal. To find that number we do:
276 - 172 = 104 metal pins.
To find the percentage that they were metal, take the number of metal pins and divide by the total number of pins:
104/276 is about 0.3768.
Multiply this by 100:
37.68
So, the percent of metal pins is 37.68%.
