Answer:
 48.
Explanation:
Given : 306.9 divided by 6.4
To find : Estimate 
Solution : We have given 306.9 divided by 6.4
We can write it as 

On removing decimal of both number 
 
.
We get 47.95
After decimal number is 9 which is greater than g os it would be rounded up 48.
Therefore, 48.