how many positive integers less than 1000 are multiples of 5 and are equal to 3 times an even integer?
I recall one time that in order to find multiples of 2 numbers, we have to multiply them. So in order to do this question, we can multiply 5*6 (which 6 comes from 3*2)=30 and 1000/30=33. But can’t we also do 3*4 since 4 is also an even integer?
I’m not sure I am following your question. Of course 3×4 is 3 times an even integer, but you’re trying to find ALL the numbers that match these criteria. That’s 5×3×2, 5×3×4, 5×3×6, etc., all the way up to 990.
(I’ve tackled this question before a few times. Here’s a link to one of those posts.)