What is the common ratio for 400,-200,100,-50

r = - 1/2

Step-by-step explanation:

To find r, divide any number in the set by the previous number in the set and reduce the fraction if possible. Check multiple numbers to make sure r is consistent between all entries ...

-200/400 = - 1/2

100/-200 = - 1/2

-50/100 = - 1/2

So r = - 1/2