What is the sum of the geometric sequence 3,12, if there are 8 terms? a) 21,845 b)43,690 c)65,535 d)87,380

  C)  65,535

Step-by-step explanation:

You can add up the 8 terms ...

  3, 12, 48, 192, 768, 3072, 12288, 49152

to find their sum is 65535.

Estimating

Knowing the last term (49152) allows you to make the correct choice, since the sum will be more than that and less than double that.

Using the formula

You know the formula for the sum of a geometric sequence is ...

  S = a1(r^n -1)/(r -1)

where a1 is the first term (3), r is the common ratio (4), and n is the number of terms (8).

Filling in the values, you find the sum is ...

  S = 3(4^8 -1)/(4-1) = 4^8 -1 = 65535

32/80  

91/140

the last one 54 doesn't go into 45. 54/100 ?

step-by-step explanation:

0,0

step-by-step explanation: