Answer :

Tenth is the first number after the decimal. If it's 5 or more than 5, then the number will increased by 1.

15.6895
Since the number after tenths is greater than 5, the number will be increased by 1

15.7 is the answer
iGreen
15.6895
     ^ This is the tenths place.

Look at the number after it, if it's 5 or more, round up, if it's 4 or less round down.

The number is 8, so we round up to 15.7.