What is 0.4/100 a fraction in it's simplest form and a decimal?​

Solve -.016x= -16. need solving this

The customer price index(cpi), which measures the cost of a typical package of customer goods,was 208.8 in 2011 and 244.1 in 2016.let x=11 corresponding to the year 2011 an estimate to cpi into 2013 and 2014. assume that the data can be modeled by a straight line and the trend to continue idenfinitely.use data points to find such a line and then estimate the requested quantities

3.4a=57.8 what is the the value of a