The national economy shrank in an annual rate of 8% per year for three consecutive years then the economy shrank by 24% over the three year. the economy actually shrank by what percentage over 3 year.

The economy is at a level that is (1 - 8%)³ = 0.778688 of the level it was at the beginning of the 3-year period. It has shrunk by

... 1 - 0.778688 ≈ 22.1%

3, 12, 48, 384, 1536, 6144, 24576, 98304

step-by-step explanation:

just keep timing it by 4.