If you flip three fair coins, what is the probability that the first two flips will both be heads, and the third flip will be either heads or tails?

Did everyone shared in the economic prosperity of the 1920’s

How have changes in transportation affected washington, d.c.

What is the main difference between primary and secondary sources? a. primary sources are historical documents, and secondary sources are modern-day documents. b. primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c. primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d. primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.