I need help with a particular SAT question:
"The first term in the sequence 3, 5, -5 is 3. Each even-numbered term is 2 more than the previous term and each odd-numbered term, after the first, is -1 times the previous term. For example, the second term is 3+2, and the third term is (-1)x5. What is the 55th term of the sequence?
a) -5
b) -3
c) -1
d) 3
e) 5

I have the answer in the practice book, but I have o idea how to solve this.

Question

I need help with a particular SAT question:
"The first term in the sequence 3, 5, -5 is 3.  Each even-numbered term is 2 more than the previous term and each odd-numbered term, after the first, is -1 times the previous term.  For example, the second term is 3+2, and the third term is (-1)x5.  What is the 55th term of the sequence?
a) -5
b) -3
c) -1
d) 3
e) 5

I have the answer in the practice book, but I have o idea how to solve this.

shubhamsrg · Answer

4th term = -3
5th =3 =1st
6th=5=2nd
.
.
.
4n+1 term =3
i.e.53rd term is 3
so 54th 5
and 55th should be -5

anonymous · Answer

3,5,-5,-3,3,5,-5,-3,3.... and so on..

you see, the numbers keep on repeating itself every 4 numbers.

the nearest multiple of 4 to 55 is 52. That means #53 is 3, #54 is 5, and finally, #55 must be -5