February 2014 Brain Teaser Solution

Q; Jack and Jill  have two children and one of the children is a boy. Assuming that the probability of each gender is 50/50.  What is the probability that the other child is also a boy? 

A: 1/3

The following are possible combinations of two children:

Boy - Girl
Girl - Boy
Boy - Boy
Girl - Girl

Out of the above options 3 contain at least one boy and only one of them has two boys.  So once you know that one of them is a boy, you can just focus on these 3 possible outcomes and since only one of the outcomes has two boys, the probability would be 1 out of 3 or 1/3

The Pleasures of Teaching to the Test: SAT and ACT

SAT tutoring is teaching to the test as the College Board book has old tests in it! as does the ACT.

I wish the Common Core testing would be as straightforward...Grades 3- 8 Math and ELA have samples of last year's test (but not the whole test).  Grades 3-8 Sample Questions
Spoiler alert: The answers are on the same page as the questions

Here is an article from the Wall Street Journal that shares my view that if kids know what is on the test, it can make them smarter and help us to focus on what are important skills and knowledge.