0

# In 1970 a desktop calculator sold for about 100.00. Today the same type of calculator sells for as little as 25.00. What is the percent of decrease in the cost of desktop calculators?

Updated: 4/28/2022

Wiki User

6y ago

In absolute terms, the percentage decrease is:

percentage change = (new - old)/old × 100%

= (25 - 100)/100 × 100%

= -75 %

Being negative it means the change is a decrease of 75%

---------------------

However, when the cost of money is taken into account it is higher - the buying power of 100 in 1970 was much more than the buying power of 100 in 2018 due to inflation.

I do not know the inflation figures for the 48 years from 1970 to 2018 - it will vary from country to country (and year to year), but if we assume an average of 5% per year (probably an under estimate), then:

100 after 48 years with average annual 5% inflation would cost 100 × (1 + 5/100)⁴⁸

percentage change = (25 - 100 × 1.05⁴⁸)/(100 × 1.05⁴⁸) × 100% ≈ -97.6 %

With inflation at about 7.177% prices double every 10 years; using this as inflation, the decrease is approx 99.1% - in other words they are almost giving the calculator away today.

Wiki User

6y ago