The consumer price index in Zeropia in 2009 relative to the year 2000 was 1.75, meaning that for every Zeropian dollar spent on consumer goods in 2000, $1.75 on average had to be spent in 2009. In Zeropian dollars, what was the increase in the price of Brand Z running shoes from 2000 to 2009, if these shoes’ price increased precisely according to the consumer price index?

(1) The price of Brand Z running shoes was $91 in 2009.

(2) The ratio of the dollar increase in the price of Brand Z running shoes to the price of the shoes in 2009 was 3:7.
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The consumer price index in Zeropia in 2009 relative to the year 2000 was 1.75, meaning that for every Zeropian dollar spent on consumer goods in 2000, $1.75 on average had to be spent in 2009. In Zeropian dollars, what was the increase in the price of Brand Z running shoes from 2000 to 2009, if these shoes’ price increased precisely according to the consumer price index?

Given that \(price_{2009}=price_{2000}*1.75\).

We need to find the value of \(price_{2009}-price_{2000}=0.75*price_{2000}\).

(1) The price of Brand Z running shoes was $91 in 2009 --> \(price_{2009}=$91\). We can find \(price_{2000}\), thus can answer the question. Sufficient.

(2) The ratio of the dollar increase in the price of Brand Z running shoes to the price of the shoes in 2009 was 3:7. This is the same information as given in the stem: (increase)/(price in 2009)=0.75/1.75=3/7. Not sufficient.

Answer: A.

Hope it's clear.
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