With the base year value 500 set to an index of 100, what is the index for a year with value 700?

An index of i means i% of the base: value = base value × index ÷ 100. The correct answer is 140.0. Traps to avoid: 1.40 comes from the "ratio not times 100" error; 40.0 comes from the "percent change not index" error; 71.40 comes from the "inverted" error; 200 comes from the "absolute difference" error.