2 + 5 + 8 +... + 143

To find the sum of the arithmetic series starting from 2 and with a common difference of 5, up to 143, you can use the formula:

Sn = (n/2)(a + L)

где Sn is the sum of the series, n is the number of terms, a is the first term, and L is the last term.

In this case, a = 2, L = 143, and n is the number of terms we need to find.

The formula for finding the number of terms in an arithmetic series is:

n = (L - a)/d + 1

where d is the common difference.

Plugging in the values, we get:

n = (143 - 2)/5 + 1 n = 141/5 + 1 n = 28.2 + 1 n = 29.2

Since the number of terms should be a whole number, we can round it down to the nearest whole number.

Therefore, the number of terms is 29.

Plugging the values into the sum formula, we get:

Sn = (29/2)(2 + 143) Sn = 14.5(145) Sn = 2102.5

The sum of 2 + 5 + 8 + ... + 143 is 2102.5.