Find the sum of the first 10

terms.

40,37,34,31, ...

40+37+34+31+28+25+22+19+16+13=265

It seems each number is 3 less than the previous number.

We must sum these 10 numbers

40, 37, 34, 31, 28, 25, 22, 19, 16, 13

The sum would equal the average of the middle 2 numbers times 10.

(28 + 25) / 2 = 53 / 2 = 26.5

We multiply by 10 because there are 10 numbers and this equals

265