What is the sum of all three digit numbers which are divisible by 20?

Explanation

Given: We need to find the sum of all three-digit numbers that are divisible by 20. Formula Used: Sum = (n/2)(first term + last term) Calculation: The first term (a) is 100, the last term (l) is 980, and the common difference (d) is 20. The number of terms (n) can be calculated using the formula: n = (l - a)/d + 1 n = (980 - 100)/20 + 1 n = 45 Now, we can calculate the sum of the arithmetic series: Sum = (n/2)(a + l) Sum = (45/2)(100 + 980) Sum = 22.5 × 1080 Sum = 24300 Therefore, the sum of all three-digit numbers divisible by 20 is 24,300.