Question

Find the sum: 25+28+31+
..+100​

Answer 1

Answer:

a = 25  

d =28 - 25 = 3

an = 100

an = a+( n - 1) d

100 = 25 + (n-1) (3)

100 -25 = (n-1) (3)

75= (n-1) (3)

75/3 = (n-1)  

25 = (n-1)  

25 +1 = n  

26 = n

Sn = n/2 (a +an)

   =  26/ 2 ( 25 +100)  

     = 13 ( 125 )

    = 1625

Step-by-step explanation:

Answer 2

Answer:

The Answer is 184.

It will help you