Inflations and Cost of Living

1.If the CPI in 2015 was 114 and in 2016 was 127, what would be the inflation rate in 2016?

2.If your current salary is $45,000 a year and the inflation rate goes up to 5% next year, what is the minimal pay raise you should ask your boss for?

3.In 2018, the Winston family spent an average of $1500 per month on groceries. According to Rule of 7, in which year would this family expect to pay double (that is, $3,000) on the same amount of groceries, assuming the inflation rate maintained at 10%?