Actually none of the answers is correct - it's neither 30,900 nor 40,000.
30,944 rounded to the nearest ten thousand will give us 30,000. It's because 30,944 is closer to 30,000 than to 40,000.
4410 is one of many numbers divisible by 5 and 9
The minimum thickness of the book would simply be the sum
of the thickness of the two cover pages and all the pages in between. That is:
minimum thickness = 0.9 mm * 2 + 0.13 mm * 400
<span>minimum thickness = 53.8 mm</span>
