For how many ordered triplets (a, b, c) of positive integers, each less than 10 is the product
abc divisible by 20?
My last math class (other than in computing) was almost sixty years ago, and I do not recall the phrase "ordered pairs" or "ordered triplets" etc. so just had to guess what was intended. Looking on google now I did not find anything useful on this, to remove any ambiguity). If permutations are pemitted/intended, of course that allows more than the 20 sequences I found. Is this something from the "new math" ?
Old dog, new tricks?
