Find 5+55+555+5555+ ... upto n terms.

Find 1 xx 5 + 3 xx 7 + 5 xx 9 + 7 xx 11 .... upto n terms.

Find the sum 5 xx 7 + 9 xx 11 + 11 xx 3 + ... upto n terms.

If (1xx3 + 2xx5 + 3xx7 + ….. upto n terms) / ( 1^3 + 2^3 + 3^3 + …… upto n terms) = 5/9, find the value of n.

Find S_n , if S_n = 1.3 + 2.4 + 3.5 + … upto n terms.