Question

Find the 113th term in the sequence
-10.5, -6.6, -2.7, 1.2, ...

A)-447.3 B) 426.3 C)430.2 D)-1172.1

Answer 1

-10.5; -6.6; -2.7; 1.2; ...

It's an arythmetic sequence:

$a_1=-10.5;\ d=-6.6-(-10.5)=3.9\\\\a_n=a_1+(n-1)d\\\\a_n=-10.5+(n-1)\cdot3.9=-10.5+3.9n-3.9=3.9n-14.4\\\\a_{113}=3.9\cdot113-14.4=440.7-14.4=426.3\\\\Answer:\boxed{a_{113}=426.3}\to\fbox{B)}$