134k views
1 vote
A sequence starts with: 390625, 78125, 15625, 3125
Work out the next four sequences.

User Carlyn
by
6.8k points

1 Answer

7 votes

Answer:

625, 125, 25, 5

Explanation:

390625, 78125, 15625, 3125

We need to find out the relationship between a number and the previous number.

We can tell that there is no common difference since 78125 - 390625 cannot possibly equal 3125 - 15625.

We can try to check if this is a geometric sequence.

78125/390625 = 0.2

15626/78125 = 0.2

3125/15625 = 0.2

Each number is 1/5 of the previous number.

3125/5 = 625

625/5 = 125

125/5 = 25

25/5 = 5

Answer: 625, 125, 25, 5

User Dkarchmer
by
7.6k points