How many even 3 digit numbers contain at least one 7. How many even 3 digit numbers contain at least one 7.
I got 126, but it was not an answer choice for the problem. Can anyone help?

The $7$ can't be in the ones place if the number is even.  That leaves the tens and hundreds place.
For all hundreds except the $700$s, there are five evens with at least one $7$: $n70, n72, n74, n76, n78$.
That accounts for $40$.
For the $700$s, there are $50$:  $700, 702, 704, ... 796, 798$.
So there are $90$ total.
