Multiple choice

If the sequence 2, 4, 2, 4, 2, 4, ... continues as shown, then the sum of the first 19 terms is _____.

  1. 62

  2. 56

  3. 54

  4. 60
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sequence is 2, 4, 2, 4, ... repeating. There are 10 pairs of (2, 4) in the first 20 terms, but we only need 19 terms. The first 18 terms consist of 9 pairs of (2+4)=6, totaling 54. Adding the 19th term (which is 2), the total sum is 54 + 2 = 56.

AI explanation

This repeating sequence has a pair of numbers (2, 4) that sums to 6. In the first 19 terms, this pair appears 9 complete times, accounting for 18 terms, plus the 19th term which is 2. The total sum is (9 multiplied by 6) plus 2, which equals 56.

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