Question

In an AP the first term is 33and the sum to first n terms is 123. Find n and d the common difference?​

Answer 1

Step-by-step explanation:

a0 = 33

sn = n/2(2a +(n-1)d)

123*2=n(66+(n-1)d)

246 =66n +(n-1)*n*d

246 is not divisible by 66

hence n# 1

let n=2

we get d= 114/2 =57

let n=3

246-198=2*3*d

48/6 =8= d

let n=4

246-264=3*4*d

-18/12 = -1.5=d