Q. what is the sum of all positive interger less than 50 that are divisible by 3
Identify Smallest/Largest Divisible Integers: Identify the smallest and largest positive integers less than 50 that are divisible by 3. The smallest positive integer divisible by 3 is 3, and the largest is 48 because 48 is the largest multiple of 3 that is less than 50.
Find Count of Divisible Integers: Find out how many integers there are that are divisible by 3 and less than 50. To find the count, use the formula for the number of terms in an arithmetic sequence: n=(last term−first term)/common difference+1. Here, the last term is 48, the first term is 3, and the common difference is 3 (since we're looking for multiples of 3). n=(48−3)/3+1=45/3+1=15+1=16.
Calculate Sum of Arithmetic Sequence: Calculate the sum of the arithmetic sequence.The sum S of an arithmetic sequence can be found using the formula S=2n×(first term+last term).Here, n=16, the first term is 3, and the last term is 48.S=216×(3+48)=8×51.
Perform Multiplication for Sum: Perform the multiplication to find the sum.S=8×51=408.