Question

Which term is −234,375 for the following sequence, assuming that the pattern continues?3, −15, 75, −375, … a8 a9 a10 a11

Answer 1

To find where the term −234,375 belong, we need to find the sequence for the nth term:

The sequence given is 3, −15, 75, −375,

Looking at the sequence we can see that if we multiply by 5 each term, it will result in the next number on the sequence.

For example:

3* 5 =15

15 * 5 = 75

75* 5 = 375

Now, we need to use the negative sign:

a2 = 3*-5 = -15

a3 = -15 * -5 = 75

a4= 75 * -5 = -375

a5= -375 * -5 = 1875

a6 = 1875* -5 = -9375

a7 = -9375* -5 = 46875

a8 =46875 * -5 = -234,375