Question

if the first term of an ap is 2 and the sum to n term is 155. find the common difference​

Answer 1

see ,

here,

a = 2

sum of nth term = 155

= n÷2 {2a+(n-1)d} = 155

= let's put n=2 , so,

= 2÷2 {2×2+(2-1)d}= 155

= 4+d=155

= d= 151 answer