Grades 3-4 Video Solutions 2023-2023_3-4

Video Transcription

Problem number 3. A gray circle with two large holes on it is put on top of a clock face, as shown. The gray circle is turned around its center. Which two  numbers is it possible to see at the same time? We see in the picture that the numbers 1 and 5 are showing. Note that there's a difference of 4 between 1 and  5. 5 minus 1 is 4. And that there are three numbers in between them. So the numbers that will show will have three numbers between them. This is a word to  pay attention to because if one number was 11, the other number could be 3, even though the difference is not 4. So let's check which of these have three numbers  between them. Choice A is 4 and 9. Here's 4 and here's 9, and there are actually four numbers in between. So this would not work. For B, we have 5 and 9,  which does have three numbers here. This should be the answer. Let's just make sure looking at the other ones. 5 and 10 have four numbers between them, so that's  not it. 6 and 9 have just two numbers, that's not it. And 7 and 12 have five numbers going this way, and even more going this way. So that's not it. The answer is B.

Video Summary

The problem involves identifying which two numbers can be visible at the same time through two holes on a rotating gray circle placed over a clock face. The key is finding pairs of numbers with three numbers between them. Initially, the pair '1 and 5' is visible, which fits the criterion. Evaluating the given choices:<br /><br />- Option A (4 and 9) has four numbers in between.<br />- Option B (5 and 9) correctly has three numbers between, making it the answer.<br />- Option C (5 and 10) and Option D (6 and 9) don't match the criterion.<br />- Option E (7 and 12) exceeds the number in between.<br /><br />The correct answer is Option B: 5 and 9.

Keywords

rotating circle

number pairs

clock face

visible numbers

correct option