The fourth term of an A.P. is ten times the first .Prove that the sixth term is four times as great as the second term.

let a a+d a+2d ...... be in AP then fourth term is a+3d given that fourth term is 10 times the first implies a+3d=10a from this d=3a 

sixth term is a+5d =a+15a=16a
​second term=a+d=a+3a=4a
​sixthterm=4timesofsecond term