I ran across a discussion of what was claimed to be a 5th grade math problem. Can you work it in your head?
A student started reading a book on Monday and read 30 pages. She read one eighth of the book on Tuesday and?ÿthe remaining quarter of the book on Wednesday. How many pages are there in the book??
(I supplied the fact that was omitted from the original, that she started on Monday. Otherwise the problem is indeterminate because she could have previously read any number of pages.)
240 pages
48
48
Check
Once upon a time, long, long ago, my 2 nieces, aged maybe 8 and 10, had a book of similar puzzles. They were having a wonderful time solving them all by trial and error. I thought I would show them that there was a better way to solve them with math - algebra. It turned out my teaching skills weren't up to the task, and we all got terribly confused as well as amused. But their father, my brother-in-law was not amused. He was furious for my ruining any chance that his kids would ever learn properly. Fortunately, both girls, now grown with kids that age of their own were better students than any of the previous generation and weren't damaged by my ineptitude.
That is tricky as it appears 30 pages equals one-eighth of a 240 page book But, that is where logic and analysis of what has been told is critical to get the correct answer, 48. It can't be true any other way. The second and third day only total to 3/8 of a book so 30 pages must represent 5/8 of the book. Thus 1/8 book equal 6 pages for a total book of 48 pages.
1/8+1/4+30(1/x)=1
30/x=5/8
x=48
NO NO NO
We can't let Fifth Graders learn about Algebra. They won't have any math classes to take in high school. Then they will forget everything by the time they are ready to go to college.
Must not allow such high-level thinking in such little bodies.
30+.125x+.25x=x
30=.625x
48=x
