From 1970 to 1980 the consumer price index increased from 38.8 to 82.4. If a container of onion dip cost $0.48 in 1970 and the price of onion dip increased at the same rate as the CPI from 1970 to 1980, by approximately how much did the price of a container of onion dip increase from 1970 to 1980

We need to find the percent increase from 38.8 to 82.4, so

x * 38.8 = 82.4

x = 82.4/38.8

x = 2.1237

Multiply by 100 to convert to percentage (move decimal 2 places to the right)

2.1237 = 212.37%

Now we can apply this percentage increase to the onion dip ...

0.48 x 212.37% =

0.48 x 2.1237 = 1.019

Round to the nearest cent $1.02 is the amount of increase. Now add it to the original price to get today's price ...

$1.02 +.48 = $1.50