CREATE TABLE table_18917 ("Country" TEXT, "Currency name" TEXT, "Month with highest inflation rate" TEXT, "Highest monthly inflation rate" TEXT, "Equivalent daily inflation rate" TEXT, "Time required for prices to double" TEXT)

how many equivalent daily inflation rate with time required for prices to double being 3.7 days
SELECT COUNT("Equivalent daily inflation rate") FROM table_18917 WHERE "Time required for prices to double" = '3.7 days'
SELECT COUNT("Equivalent daily inflation rate") FROM "table_18917" WHERE "Time required for prices to double" = '3.7 days'