Question: When did the king size bed come out?

context: No context provided
question: When did the king size bed come out and become standardized?
short_answers: mid-1950s
1950s and 60s
1950s and 1960s
context: The sizes of mattresses use non-numeric labels such as a "king" or "full", but are defined in inches. Historically most beds were "twins" or "doubles" but in the mid-1940s larger mattresses were introduced by manufacturers. These were later standardised as "queen" and "king", and first made a significant impact on the market in the 1950s and 60s. Standard mattress depth ranges from the "standard" size of to "high contour" of up to . Below are the standard ISPA widths and heights in the United States and Canada. U.S. bed sizes usually have a length of either , while UK bed sizes usually have a length of either . Widths also differ between the U.S. and UK standards.
question: When did the king size bed first come out?
short_answers: mid 1940s
mid-1940s
context: No context provided
question: When were king sized beds standardised in North America?
short_answers: mid-1950s
1950s and 1960s
context: The sizes of mattresses use non-numeric labels such as a "king" or "full", but are defined in inches. Historically most beds were "twins" or "doubles" but in the mid-1940s larger mattresses were introduced by manufacturers. These were later standardised as "queen" and "king", and first made a significant impact on the market in the 1950s and 60s. Standard mattress depth ranges from the "standard" size of to "high contour" of up to . Below are the standard ISPA widths and heights in the United States and Canada. U.S. bed sizes usually have a length of either , while UK bed sizes usually have a length of either . Widths also differ between the U.S. and UK standards.
question: When were king sized beds introduced by manufacturers in North America?
short_answers: mid 1940s
mid-1940s

Answer: Standard bed sizes are based on standard mattress sizes, which vary from country to country. The sizes of mattresses use non-numeric labels such as a "king" or "full", but are defined in inches. Historically most beds were "twins" or "doubles" but in the mid-1940s larger mattresses were introduced by manufacturers. These were later standardised as "queen" and "king" in the mid-1950s and 1960s and first made a significant impact on the market during this time period.