Question

the librarian at the public library counted the number of books on each shelf.
books per shelf
number of shelves
1-10
11-30
21-30
31-40
41-50
51-60
61-70
71-80
81-90
91-100
number of books
how many shelves are there in all?
shelves
submit
work it out
2
questions
unanswered
time
elapsed
00
01
45
19
smartscore
out of 100
video

Explanation:

Step1: Count the number of shelves in each category

• \(1 - 10\): \(5\) shelves
• \(11 - 20\): \(4\) shelves
• \(21 - 30\): \(4\) shelves
• \(31 - 40\): \(0\) shelves
• \(41 - 50\): \(4\) shelves
• \(51 - 60\): \(1\) shelf
• \(61 - 70\): \(5\) shelves
• \(71 - 80\): \(4\) shelves
• \(81 - 90\): \(4\) shelves
• \(91 - 100\): \(0\) shelves

Step2: Sum up the number of shelves

$$5 + 4+4 + 0+4 + 1+5 + 4+4+0=31$$

Answer:

\(31\)