Sum of following series 4.1+5.2+6.3+7.4+....52.49

looks like you have an AS,

where a=4.1 , d = 1.1 and n = ??
so we have to first find what term number if 52.49
a+(n-1)d = term(n)
4.1 + (n-1)(1.1) = 52.49
1.1(n-1) = 48.39
n-1 = 43.99 ???????
something wrong here, n has to be a whole number

closest is n = 45
check
term 45 = 4.1 + 44(1.1) = 52.5

52.49 cannot be a term in the sequence
check you question or typing