Round off value of 78.25m to nearest 10 m is: -
A) 77m
B) 78m
C) 80m
D) None of these

Hint: Here we will first evaluate the interval in which the given number lies and then find the nearest value to the given decimal number to round it off.

Complete step-by-step answer:
The given number is 78.25 and we have to round it off nearest to 10m.
Now we know that, the given number 78.25 lies in the interval:-
\[78 < 78.25 < 79\]
Now since, it can be seen that 78.25 is nearest to 78.
Therefore, we can round off 78.25 to 78.

Therefore, option B is the correct option.

Additional Information:
The general rule for rounding off the numbers: -
If the number ends with 5, 6, 7, 8 or 9 then the number gets rounded off to next and nearest ten.
Eg: - 29 can be rounded off to 30.
If the number ends with 0, 1, 2, 3 or 4 then the number gets rounded off to previous and nearest ten.
Eg : - 21 can be rounded off to 20.
For rounding off the decimals we need to observe the decimal place which we have to round off.
If we have to round off nearest to tenth then we have to observe the number after the decimal at tenth place and then round it off accordingly.

Note: Students should note that we had to round off the number nearest to ten therefore, we have observed the number at the tenth place after the decimal which is 2 and then rounded off according to the rule.