Question

read the passage.
the electric washing machine was invented in the 1900s, ushering in a new age of domestic cleaning. unfortunately, the first machines were quite expensive, so most people continued to hand - wash their clothes and linens. in 1934, a man named c.a. tannahill opened the first public laundry space. at his \laundromat,\ people paid a small fee to use one of many machines on the premises. this opened electric washing to many more people. by the 1950s, laundromats had drying machines, too. whats more, the machines accepted coins directly from customers. this meant that workers were no longer needed to collect money on site - and unattended laundromats could stay open all day and night!
what is the main, or central, idea of the passage?
washing machines werent practical for most people until the arrival of the twenty - four - hour laundromat.
the hard work of hand - washing clothing inspired c.a. tannahill to create the electric washing machine.
laundromats, developed for convenience and affordability, continued to improve over time.
public spaces like laundromats adjust slowly over time to ensure low prices and access to everyone.

Explanation:

The passage starts by introducing the electric washing machine's invention in the 1900s but notes its high cost initially. Then it talks about C.A. Tannahill opening the first public laundry (laundromat) in 1934 which made electric washing accessible to more people. It further mentions that by the 1950s, laundromats had drying machines and coin - operated systems (so they could be unattended and open 24/7). This shows the development of laundromats over time in terms of convenience (like being open all day and night) and affordability (small fee to use machines).

Answer:

Laundromats, developed for convenience and affordability, continued to improve over time.