Directions: One term in the given number series is incorrect. Find out the wrong term.

61440, 1920, 120, 15, 4.5, 1.875

The correct answer is 4.5.

To find the wrong term in the given number series, let us analyze the pattern of operations between consecutive terms from left to right:

1. First term to second term:
$61440÷32=1920$
Here, the term is divided by 32.

2. Second term to third term:
$1920÷16=120$
Here, the term is divided by 16.

3. Third term to fourth term:
$120÷8=15$
Here, the term is divided by 8.

Notice the pattern of the divisors: 32, 16, 8... Each divisor is halved (divided by 2) to get the next divisor.

4. Fourth term to fifth term:
Following the pattern, the next divisor should be:
$8÷2=4$
Dividing the fourth term (15) by 4 gives:
$15÷4=3.75$

5. Fifth term to sixth term:
The next divisor after 4 should be:
$4÷2=2$
Dividing 3.75 by 2 gives:
$3.75÷2=1.875$
This matches the last term in the given series.

Therefore, the fifth term in the series should be 3.75 instead of 4.5. Hence, 4.5 is the incorrect term.