Last visit was: 25 Apr 2024, 19:51 It is currently 25 Apr 2024, 19:51

Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Kudos
Tags:
Show Tags
Hide Tags
Tutor
Joined: 16 Oct 2010
Posts: 14823
Own Kudos [?]: 64924 [0]
Given Kudos: 426
Location: Pune, India
Send PM
GMAT Club Legend
GMAT Club Legend
Joined: 08 Jul 2010
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Posts: 5960
Own Kudos [?]: 13387 [0]
Given Kudos: 124
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Send PM
Director
Director
Joined: 17 Dec 2012
Posts: 589
Own Kudos [?]: 1519 [0]
Given Kudos: 20
Location: India
Send PM
Intern
Intern
Joined: 06 Apr 2017
Posts: 21
Own Kudos [?]: 102 [0]
Given Kudos: 38
Location: United States (OR)
Concentration: Finance, Leadership
GMAT 1: 730 Q49 V40
GPA: 3.98
WE:Corporate Finance (Health Care)
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Quickly decide to use brute force. Count the number of matching cases in each group of ten numbers.

70 => 0
71 => 4
72 => 3
73 => 4
74 => 3
75 => 4
76 => 3
77 => 0
78 => 3
79 => 4
80 => 0
81 => 3
82 => 2
83 => 3
84 => 2
85 => 3
86 => 2
87 => 3
88 => 0
89 => 3
90 => 0
91 => 4
92 => 3
93 => 4
94 => 3
95 => 4
96 => 3
97 => 4
98 => 3
99 => 0

4*8 + 3*13 + 2*3 = 77

Posted from GMAT ToolKit
Director
Director
Joined: 17 Dec 2012
Posts: 589
Own Kudos [?]: 1519 [0]
Given Kudos: 20
Location: India
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Expert Reply
Top Contributor
twixt wrote:
How many even 3 digit integers greater than 700 with distinct non zero digits are there ?

A. 729
B. 243
C. 108
D. 88
E. 77

These types can be handled by considering the number of possibilities for each digit. Start with the one with the most constraints.
1. Last digit can be 2,4,6,8 when the first digit is 7 or 9 and 2,4,6 when the first digit is 8. So there are 4 possibilities in the first case and 3 possibilities in the second case for the last digit.
2. Middle digit cannot be one of the first and last digits and cannot be 0. So there are 7 possibilities
3. When first digit is 7 or 9, then we have (4*7) + (4*7)=56
4. When first digit is 8, we have 3*7=21
5. Total is (3)+(4)= 77
Intern
Intern
Joined: 17 Apr 2017
Posts: 10
Own Kudos [?]: 11 [0]
Given Kudos: 18
Location: India
Schools: NTU '20 (S)
GMAT 1: 720 Q48 V40
WE:Analyst (Consulting)
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
[E]



Lets go digit wise:

A B C, A is the hundredth digit and C is the ones digit.

As ABC is a three digit greater than 700, A can have values 7,8,9 ( 700<ABC<999)
As ABC is a even number then, C can take values 2,4,6,8

Now Imagine A is 7, and C can take 2,4,6,8 for each of these possibilities of C there are 7 different values B can take up (except 7,0,and the one in C as the digits are unique)

Therefore for A = 7, there are 4*7 = 28 numbers
for A = 8 there are 3*7 (as 8 is already used and C can take only 2,4,6 as its even) = 21
for A = 9 there are 4*7 = 28 numbers

Adding, 28+21+28 = 77
Intern
Intern
Joined: 27 Jul 2018
Posts: 16
Own Kudos [?]: 47 [0]
Given Kudos: 35
GMAT 1: 710 Q48 V40
GPA: 4
Send PM
How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Bunuel

712 756 812 856 912 956
714 758 814 858 914 958
716 762 816 862 916 962
718 764 818 864 918 964
722 766 822 866 922 966
724 768 824 868 924 968
726 772 826 872 926 972
728 774 828 874 928 974
732 776 832 876 932 976
734 778 834 878 934 978
736 782 836 882 936 982
738 784 838 884 938 984
742 786 842 886 942 986
744 788 844 888 944 988
746 792 846 892 946 992
748 794 848 894 948 994
752 796 852 896 952 996
754 798 854 898 954 998

Count: 108 [Horizontal*Vertical = 6*18]
Answer is C
Intern
Intern
Joined: 27 Jul 2018
Posts: 16
Own Kudos [?]: 47 [0]
Given Kudos: 35
GMAT 1: 710 Q48 V40
GPA: 4
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Poor me.. Thank you Bunuel
Intern
Intern
Joined: 17 Jun 2019
Posts: 23
Own Kudos [?]: 6 [0]
Given Kudos: 30
Location: Israel
Concentration: Technology, Leadership
GPA: 3.95
WE:Engineering (Computer Hardware)
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
working in a table writhing down possible combinations for units, tenths and hundreds worked for me
Manager
Manager
Joined: 10 Aug 2018
Posts: 228
Own Kudos [?]: 141 [0]
Given Kudos: 179
Location: India
Concentration: Strategy, Operations
WE:Operations (Energy and Utilities)
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
The answer has to be 77.
I did it this way:
If the number starts with 7 then we will have 1x7x4 ways=28
If the number starts with 8 then we will have 1x7x3 ways=21
If the number starts with 9 then we will have 1x7x4 ways=28
Total 77 ways.
We have to keep in mind that the numbers should be NON ZERO, DISTINCT, and EVEN. Any mistake in getting these three together will get us to the wrong answer.
Director
Director
Joined: 16 Jun 2021
Posts: 994
Own Kudos [?]: 183 [0]
Given Kudos: 309
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
twixt wrote:
How many even 3 digit integers greater than 700 with distinct non zero digits are there ?

A. 729
B. 243
C. 108
D. 88
E. 77


Starting with 7 the total possibilities are 7* 4 (2,4,6 ,8 )

Starting with 8 the total possibilities are 7* 3(2,4,6)

Starting with 9 the total possibilities are 7*4

=>28*2 + 21 =77

Therefore IMO E
Manager
Manager
Joined: 13 Mar 2021
Posts: 63
Own Kudos [?]: 31 [0]
Given Kudos: 20
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
ABC

7<=A<=9
C= (2,4,6,8)
B = (1,2,3,4,5,6,7,8,9)

A=7
So C can have 4 Values and B can have 7 values= 7x4=28

A=8
So C can have 3 values and B can have 7 values= 7x3= 21

A=9
So C can have 4 values and B can have 7 values= 7x4= 28


Total 77 Values.
Answer is E.
Intern
Intern
Joined: 07 Sep 2021
Posts: 15
Own Kudos [?]: 3 [0]
Given Kudos: 15
Location: Taiwan
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
I can provide a different approach here:

recap: 3 digits, no zero, even, and distinct

ok so we can all agree here we have 712-987

so in the hundreds digit we have 7,8,9 which is 3 option

tenth and units are 8 and 7 separately, so the answer is 3*8*7 = 168

ohhh oops remember the question only requires even numbers so 2,4,6,8 out of 9 digit which gives us a 4/9 times 168=75

go for the closest answer E
GMAT Club Legend
GMAT Club Legend
Joined: 03 Jun 2019
Posts: 5344
Own Kudos [?]: 3964 [0]
Given Kudos: 160
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Asked: How many even 3 digit integers greater than 700 with distinct non zero digits are there ?

If hundred digit is 7 or 9 (2 options), unit digit will have 4 options (2,4,6,8) and tens digit will have 9 - 2 = 7 options. Total such numbers formed = 2*4*7 = 56
If hundred digit is 8 (1 options), unit digit will have 3 options (2,4,6) and tens digit will have 9-2 = 7 options. Total such numbers formed = 3*7 = 21
Number of even 3 digit integers greater than 700 with distinct non zero digits = 56 + 21 = 77

IMO E
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32680
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: How many even 3 digit integers greater than 700 with distinct non zero [#permalink]
   1   2 
Moderators:
Math Expert
92915 posts
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne