Hi guys & Girls Ive come across this question in my assignment for math, surely i dont have enough information to get an answer?

The Sum of the first10terms of an arithmetic series is165and the sum of the next10terms is445. Find the sum of the terms21-30.

SUM = n/2 [2a (n-1)]d

n= number of terms (10 for each formula as only 10 terms are added together i.e.1->10=10 and 11->20=10???)

a =First Term in series (None given)

d= Common difference (also not given)

445 = 20/2 [2a (20-1)]d

165 = 10/2 [2a (10-1)]d

can't use linear equation there becauseafor the445will be different fromafor165,anddisnt known

all the other formulae i have come across either requiredor at least a couple of values in the sequence so I can work outd

pfft, surely it's impossible?