we have an arithmetic sequence with
a0 = 1st 3-digit number divisible by 13
a0 = 104
d = 13 (why?)
last term is largest divisible by 13 = 988
how many terms? (988-104)/13 + 1 = 69
S = 69/2(104+988) = 37674
Find the sum of all 3 digit whole numbers that are divisible by 13.
3 answers
MATHS
YES