its C
One coffee maker's cost in 1983 was $20.85 if the current CPI is 153 option (a) is correct.
It is given that the CPI is currently 153 if a coffee maker costs $31.90 today. It is required to find how much did one cost in 1983.
It is defined as the tool to measure inflation that indicates between two periods how much cost is increased. It can be represented by [tex]\rm CPI_t[/tex] for the given time 't'
The formula for finding the CPI:
[tex]\rm CPI_t = \frac{C_t}{C_0}\times 100[/tex]
Where [tex]\rm c_t[/tex] is the cost in the current market
[tex]c_0[/tex] is the cost at the given period.
We have in the question:
[tex]\rm c_t = \$31.90\\\\\rm CPI_t = 153[/tex]
Putting these values in the CPI formula, we get:
[tex]\rm 153= \frac{31.90}{C_0}\times 100\\\\\rm c_0 = \frac{3190}{153} \\\\\rm c_0 = \$20.84 \approx \$20.85[/tex]
Thus, one coffee maker's cost in 1983 was $20.85 if the current CPI is 153.
Learn more about the CPI here:
https://brainly.com/question/26682248
