Question

if in an A.P 1 + 6 + 11 +...........+x=189 find the value of x?

Answer 1

a+(n-1)d=189
1+(x-1)5=189
5x-5 =189-1
5x-5=188
5x=188+5
5x=193
x=193
x=38.6 is answer