Answer: 20000
This is the value 20 thousand, which can be written as 20,000
In scientific notation it is 2 * 10^4
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Step-by-step explanation:
The zeros in this case are not significant. Currently 15000 has 2 significant figures (abbreviates to "sig fig").
We want 1 sig fig, so we have to decide whether to keep the the number in the ten-thousands digit or the thousands digit. We always go for the left most nonzero digit since it's more significant.
Then we round 15000 to the nearest ten thousands place. One could argue that this number is right at the midpoint of 10 thousand and 20 thousand. It seems like it's a coin toss. Though convention is to round up when we're stuck at the midpoint like this. In some rare cases, rounding down is beneficial. It all depends on context.
So 15000 rounds to 20000 when rounding to the nearest ten thousands place value, i.e. when we round to 1 significant figure.
When converting to scientific notation, we get the value 2 * 10^4
At this point, it's much more clear we have 1 sig fig now.