This is a complex subject, so bear with me. One of the first manufacturers of kits was based in the U.K., long before metric measurements were imposed on us, and he decided that the ideal would be to have a 6' (6 feet) tall man represented by a figure 1" (1 inch) tall, whch gave the original scale of 1/72 (or 1:72) since there are 72 inches in 6 feet.
For some reason railway modellers decided to make things really complicated, so combined metric with imperial, making 4mm = 1 foot, which began the 1/76 scale, aka "OO" gauge; they also decided that another scale should be 7mm = 1 foot, which became 1/43 scale, aka "O" gauge. They went a little less complicated with Gauge 1, making that 1" to 2'8" (32 inches) or 1/32 scale.
When Tamiya started, they assumed that the world would accept metric scales (it didn't) so produced aircraft to 1/100 scale; this drew a general "raspberry" ("Bronx cheer," in the U.S.,) and it fell flat, largely because Airfix and others had caught on to 1/72, and it was the perfect scale for schoolchildren, since it didn't take up too much room.
However, Tamiya had also decided to produce military vehicles, preferably with electric motive power, and found that 1/35 was the ideal scale in which to fit their electric motors, and that did stick, probably because there was no other scale to compete.
Manufacturers in the U.S. began to produce 1/48 scale, or 1" to 4' (1:48 ) since there are 48 inches in 4 feet; Revell also started to produce 1/32 aircraft kits, maybe to match the railway Gauge 1, or possibly because there's a heck of a lot more elbow room in the U.S.
Airfix countered this, by starting their 1/24 range of aircraft, which caught the rest of the world on the hop, being totally unexpected.
Revell, also, for some unknown reason, decided to make a "fit-the-box" series, in which the criteria seemed to be 1/. fix on a box size, then 2/. make a kit to fit inside; this gave rise to some really weird scales, too numerous to mention here (and I can't remember them all, either.)
There is a (sort of) logical reason for the two car scales of 1/24 1/25, but that's beyond my fading memory.
Edgar