2 votes

Choose the most appropriate option.

$4, 7, 25, 10, \underset{\text{_____}}{?}, 20, 16, 19$

- $13$
- $15$
- $20$
- $28$

1 vote

Two series alternate here, with every third number following a different pattern.

In the main series, $3$ is added to each number to arrive at the next.

In the alternating series 5 is subtracted from each number to arrive at the next.

$4,7,10,13,16,19$ is one series.

$25,20$ is another series.

so missing number is $13$

Option $A$ is correct.

In the main series, $3$ is added to each number to arrive at the next.

In the alternating series 5 is subtracted from each number to arrive at the next.

$4,7,10,13,16,19$ is one series.

$25,20$ is another series.

so missing number is $13$

Option $A$ is correct.