Answer:
50,000
Explanation:
when we say significant digits we mean the numbers that matter when stating the value of the number.
0.00030 can be written as 0.0003 without affecting it's value, the last zero is not significant.
50,000 all of the numbers here are significant to its value if we take away a zero it becomes 5,000 which is not equal to 50,000. so every digit here is significant
100.0300 can be written as 100.03 without loosing any value
500.00 can be written as 500 without loosing any value. ( think of this as $500.00, this also equals $500)
