PSAT Math problem.. please help and explain
Favorites|Homepage
Subscriptions | sitemap
HOME > > PSAT Math problem.. please help and explain

PSAT Math problem.. please help and explain

[From: ] [author: ] [Date: 12-07-16] [Hit: ]
51, 52, and so on.From 50-59, there are 10 numbers, and from 100-1000,......
How many different three-digit numbers between 100 and 1,000 have 5 as the tens digit?
A. 9
B. 10
C. 50
D. 89
E. 90

What is the answer? and please explain, this question is really driving me crazy.

-
E. 90
If you think about it, every number that has 5 as the tens digit will either be 50, 51, 52, and so on.
From 50-59, there are 10 numbers, and from 100-1000, there are 9 "sets" of these 50-59's, i.e.150-159, 250-259, etc.
Knowing this, you can just multiply 9 and 10, which gives you 90.

I think I'm right, but if I'm not, I'm terribly sorry... Good luck!

-
This question is technically asking you how many three-digit numbers have 5 as the second digit.

So We have the following:

150 - 159 = Total of 10 numbers

Now there are 900 total three digit numbers between 100 and 1000, so just mutiply the 10 by 9 to get your answer.

10*9 = 90 numbers

E

-
You are dealing with 9 sets of 100 (i.e. 100, 200, 300, etc.).
For each set of 100, you have a range from 50-59 (10 numbers) where there is a 5 as the tens digit.
So, 10*9=90
1
keywords: please,problem,and,PSAT,explain,help,Math,PSAT Math problem.. please help and explain
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .