Question

Question 6 options:
The terms 6, x, y, 18 form a geometric sequence. What is the value of y, correct to two decimal places?

Answer 1

Let the common ratio = r
Then the terms in the sequence are
\[6, 6r, 6r ^{2},6r ^{3}\]
the last term is 18 therefore
\[6r ^{3}=18\]
\[r ^{3}=\frac{18}{6}=3\]
Can you find the value of r now?