How many integers between 324,700 and 458,600 have tens digit 2 and

Question

How many integers between 324,700 and 458,600 have tens digit 2 and units digit 1? A. 1,339 B. 1,352 C. 1,353 D. 10,030 E. 10,300 Untitled1.jpg

Bunuel · Accepted Answer

There is one number in hundred with 2 in th tens digit and 1 in the units digit:  21 , 1 21 , 2 21 , 3 21 , ...

The difference between 324,700 and 458,600 is 458,600-324,700=133,900 - one number per each hundred gives 133,900/100=1,339 numbers.

Answer: A.

Hope it's clear.

KillerSquirrel · Answer

Using the probability method N = 458,600 – 324,700 = 133,900 P = 1/10*1/10 = 1/100. P*N = 1/100*133,900 = 1,339 And the answer is (A)

Ravshonbek · Answer

have fun!

bibha · Answer

Hey,
Great thinking. 
Thx.

GMATBLACKBELT720 · Answer

Find the number of integers between the two.

458600-324700 = 133900. Now we need to figure out how many instances there will be a 2 in the tens and a 1 in the units. The easiest way to do this is to see that per 100 integers (0-100) only 21 suffices the conditions. Thus, per 100 integers there is only 1 instance.

133900/100 = 1339.

A

ScottTargetTestPrep · Answer

The first few integers that have this property are: 324,721, 324,821, 324,921, …. As we can see, this is an arithmetic sequence with common difference of 100. Since the last integer that has this property is 458,521, the number of integers that have this property is:

(458,521 - 324,721)/100 + 1 = 133,800/100 + 1 = 1,338 + 1 = 1,339

Answer: A

hetankhatri · Answer

The number of numbers in an interval between two different multiples of 100 which end in the two-digit number 21 is equal to the number of 100 digit intervals between those two multiples of 100.

Calculate the number of 100 digit intervals between those two numbers.

(458,600 - 324,700) / 100

= 4586 - 3247

= 1339

nikitathegreat · Answer

Since the questions asks about the no. between the two integers that means the first and last integer will not be included. How many integers are between 2 and 5 is not 5 -2 =3 because the no. of integers are 3 & 4 only. So, how did we derive at 133900?

1616 · Answer

How many integers between 324,700 and 458,600 have a 2 in the tens digit and a 1 in the units digit?
A 1,339
B 1,352
C 1,353
D 10,030
E 10,300
There is one number in hundred with 2 in th tens digit and 1 in the units digit: 21, 121, 221, 321, ...

The difference between 324,700 and 458,600 is 458,600-324,700=133,900 - one number per each hundred gives 133,900/100=1,339 numbers.

Answer: A.

Hope it's clear.Hello Bunuel , @ScottTargetTestPrep,
While counting the number of integers between 324700 and 458600 --> We should count all the numbers between 324701 and 458599 inclusive both, Then the total number should be 133899 and not 133900, Am i mistaken, Can you please help why it is 133900?

bumpbot · Answer

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How many integers between 324,700 and 458,600 have tens digit 2 and

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How many integers between 324,700 and 458,600 have tens digit 2 and

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