Hi! I’m a bit confused with this problem. I understand plugging in with the [ (last - first)/N ] +1 equation. So (500-310/5)+1 which gives us 39. But I thought the odd number signified a middle number that we had to find?So I thought 810 x 38+ (810/2) = 24,705 would be the answer. Because 38 multiples plus the middle number.
Your method is fine, but remember there’s 39 integers. This is \frac{38}{2} = 19 pairs and the middle value. Not 38 pairs.