Question

If the 3rd and 6th term of a G.P. are 20 and 160 respectively then what is the 1st number?

Answer 1

As the Value of r Cube= 8

Then Value of r=2

So the Value of a=5

Answer 2

your answer is 5

a is the first term and r is the common ratio

refer to attachment

hope it helps

:-)