5(n-1/10)=1/2=n=1/5 OR n=0.2
The answer here is the answer (a). This is because it only makes sense to just read the problem and see that the water stands in race A are closer together.
Answer:
r=3 where r is the common ratio
Step-by-step explanation:
The sum of geometric progression for n terms is given by:
, where is the
first term of the series and r is the common ratio.
Now, according to the question, there are four terms and they form a geometric progression. So sum of four terms is given as and .
Also according to the above formula:
Using the values as given in the question into the above equation we get:
[ Using formula ]
which is the required answer.