If the sequence 2 , 4 , 2 , 4 , 2 , 4 , ... continues as shown, then the sum of the first 19 terms is _____?
We can see 2 is in the odd places and 4 in the even places.
In the 1st 18 terms, there are 9 4's and 2's which sum up to 54 and the 19th term being 2 is added to get sum of 1st 19 terms as 56.
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