from 1960 to 1970, the consumer price index (CPI) increased from 29.6 to 38.8 if a dozen tangerines cost 0.31 in 1960 and the price of tangerines increase at the same rate as the CPI from 1960 to 1970, approximately how much did a dozen tangerines cost in 1970

A consumer price index measures the average price changes of goods that are bought by people in an economy. It shows the level of inflation in an economy.

To calculate the cost of a dozen tangerines in 1970we have to know the percentage increase in price index from 1960 to 1970 and this will be:

= [(38.8 – 29.6) / 29.6] × 100%

= (9.2 / 29.6) × 100%

= 31.08%

Let's represent the price of a dozen tangerines in 1970 by X and solve. This will be:

31.08 = (X - 0.31) × 100 / 0.31

Cross multiply

(31.08 × 0.31) = 100X - 31

9.6348 = 100X - 31

100X = 9.6348 + 31

100X = 40.6348

X = 40.6348 / 100

X = 0.46348

X = 0.41

Therefore, the cost of a dozen tangerines in 1970 is $0.41