10,20,40,80... find the common ratio for the geometric sequence

2

Step-by-step explanation:

So the common ratio is simply what a number can be multiplyied by. To find this, all we have to do is see how many times one number goes into the one after it.

So lets take the 20(2nd number), lets divide it by 10(1st number). What do we get when we divide the numbers? We get 2. since 10 goes into 20, 2 times.

Lets see if the common ratio 2 checks out for the other numbers. What is 80(4th number) divided by 40(3rd number)? Well again, thats 2. Since 40 goes into 80, 2 times.

So, we can conclude that the answer is 2.