Problema Solution

Use Gauss's approach to find the following sum(do not use formulas)What is the sum of the sequence:

3+8+13+18+...+68

Answer provided by our tutors

3+8+13+18+...+68 =


3 + 68 = 71


8 + 63 = 71


3 = 3 + 0*5


8 = 3 + 1*5


13 = 3 + 2*5


68 = 3 + 13*5


this means there are total of 14 numbers on the sequence: 3, 8, 13, 18,...,68


14/2 = 7


3+8+13+18+...+68 = 7*71 = 497


the sum of the sequence is 497.