Question

find the sum of all multiples of 3 between 97 and 154​

Answer 1

Answer:

2394

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

Let the multiples of 3 from 97 to 154 be,

99, 102, 105, 108............153

Here, a=99, d=3, and an=153(last term)

So, to find no.of terms b/w 99 and 153,

an=a+(n-1)d

=> 153= 99+(n-1)3

=> 153-99= (n-1)3

=> 54/3=n-1

=> 18+1=n

=>n=19....

So, sum of 19 terms is, S19=n/2[a+an]

=> 19/2[99+153]

=> 19*126

=> 2394.......