Question

45+46+47+48+40+50+...........+113+114 = ?

Answer 1

a1 =45 , an = 114 & d = 1

(since these are in AP)

Since an = a + (n-1)d = 45+(n-1) q

=> 114 - 45 = n-1

=> 115 - 45 = n

=> 70 =n

Sn = n /2 (2a + an)

= 70÷2 (2*45 +114)

= 35 (90 + 114)

=7140

Answer 2

Hey Mate!!!

The given series is in ap as the common difference is same

a = 45. d = 46-45 = 1. an = 114

an = a + ( n-1 ) d

114 = 45 + ( n - 1 )

114 - 44 = n

n = 70

Where n is no. of terms

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

Sn = 35 [ 2( 45 ) + 69]

Sn = 5565

Where Sn is sum of n terms

Have a nice time