How did easy credit contribute to the boom times in the 1920s?

just read explantation

Explanation:

The Easy credit of the 1920's saw a massive increase in consumer indebtedness, together with an equally dramatic decline in savings. 75% of the population spent most of their yearly income to purchase goods including food, clothes, radios, and automobiles. Consumer Credit outstanding in 1929 totaled over $3 Billion.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

i believe it was the shinto