I did my PPL in 38 hours: there was a PPL "approved course" in those days. By the time I was instructing, 40 was the min: only students with continuity and ability finished in anything like that number.
Most ex-FS cadets finished in just under 45- flying every day for a month helps! Best non-FS stude I ever had came in Saturday and Sunday every weekend, and every Bank Holiday, and finished in about 4 months, only having flown 43 hours. Fortunately, he finished before his wife could take out a contract on me!
Of course, being an excellent stude, he also came closer to killing me than any of the others- because he was good, I let my guard down in a situation which he couldn't quite handle. I learnt about instructing from that!