Question

The sum of first five multiples of 3 is a.45 b. 65c. 75 d. 90

Answer 1

Answer:

a. 45 is the answer

Step-by-step explanation:

3+6+9+12+15

Answer 2

Answer: a.45

Step-by-step explanation:

It is a question from Arithematic progration

here, a=3.....................first number

 d=3 ..........................common difference

n=5 ......................first five multiples

to find: Sn=?

Sn=n/2[2a+(n-1)d]......................formula

    =5/2 [2x3+(5-1)3]

    =5/2 [6 +4x3]

    =5/2(6+12)

    =5/2(18)

    =5 x 9

    = 45

therefore sum of first five multiples of 3 is 45.