Question

What is tye value of the fourth term in a geometric sequence for which a1=15 and r=1/3

Answer 1

$a_1=15;\ r=\dfrac{1}{3}\\\\a_4=a_1r^3\to a_4=15\cdot\left(\dfrac{1}{3}\right)^3=15\cdot\dfrac{1}{27}=\boxed{\frac{5}{9}}$