What is the 43rd term of an arithmetic sequence with a rate of increase of -6 and a11 = 12?

A. -174
B. -176
C. -180
D.-186
E. -240

Question

What is the 43rd term of an arithmetic sequence with a rate of increase of -6 and a11 = 12?

A. -174
B. -176
C. -180
D.-186
E. -240

hartnn · Answer

so, d=-6 
a11= 12
firstly,use the formula $\large a_n=a_1+(n-1)d$
to get the value of a1 (n = 11)

anonymous · Answer

A little confused still

hartnn · Answer

$a_n=a_1+(n-1)d$
is the general formula
we are given, a11 =12   ....so,n=11
d=-6
just plug these in and find the value of a1

amistre64 · Answer

just let a11 = a1

a(11-10) = a1

 a(43-10) = a33

anonymous · Answer

Isn't the answer -174?

amistre64 · Answer

or in this case it might be even simpler to go to a0

an = 12 - 6n;

a(43-11) = a32 = 12 -6(32)

anonymous · Answer

The answeris A?

amistre64 · Answer

of course not ...

amistre64 · Answer

12 - 6(32)

hartnn · Answer

how did u get -174 ? 
its actually 42nd term...

anonymous · Answer

180! Yes? And i'm in summer school. And my math teacher isnt here, so when my science teacher helped me I guess he was wrong..

amistre64 · Answer

logically:  43 - 11 = 32  so you are 32 interation away.

32(-6)  must be added to 12

hartnn · Answer

-180 yes, but more important is that you know exactly how to get it...

amistre64 · Answer

*iterations ... my fingers hate me

anonymous · Answer

Thank you both.

hartnn · Answer

welcome ^_^

amistre64 · Answer

good luck ;)