GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 15 Dec 2018, 03:56

### 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

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

## Events & Promotions

###### Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### Free GMAT Strategy Webinar

December 15, 2018

December 15, 2018

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# What are the last two digits (at ten's place and unit’s place) in the

Author Message
TAGS:

### Hide Tags

Manager
Joined: 07 Jun 2017
Posts: 174
Location: India
Concentration: Technology, General Management
GMAT 1: 660 Q46 V38
GPA: 3.6
WE: Information Technology (Computer Software)
What are the last two digits (at ten's place and unit’s place) in the  [#permalink]

### Show Tags

24 Oct 2017, 00:35
1
3
00:00

Difficulty:

95% (hard)

Question Stats:

29% (02:05) correct 71% (01:41) wrong based on 54 sessions

### HideShow timer Statistics

What are the last two digits (at ten's place and unit’s place) in the numerical value of the following product?

243 x 5787 x 5315 x 7779 x 8262 x 3179 x 993.

A. 10
B. 30
C. 50
D. 70
E. 90

_________________

Regards,
Naveen
email: nkmungila@gmail.com
Please press kudos if you like this post

Math Expert
Joined: 02 Aug 2009
Posts: 7107
What are the last two digits (at ten's place and unit’s place) in the  [#permalink]

### Show Tags

24 Oct 2017, 05:54
nkmungila wrote:
What are the last two digits (at ten's place and unit’s place) in the numerical value of the following product?

243 x 5787 x 5315 x 7779 x 8262 x 3179 x 993.

A. 10
B. 30
C. 50
D. 70
E. 90

hi..

we have numbers with 2 and 5, so UNIT's place is surely 0..
here we have to find the tens digit too..

this will be given by $$5315*8262..... 15*2=30$$

rest all numbers we require to concentrate on only the UNITs digit
$$243 * 5787 * 7779 * 3179 * 993.......3*7*9*9*3....21*81*3......1*1*3=3$$

so LAST two digits are 30*3=90

E
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor

Director
Joined: 06 Jan 2015
Posts: 529
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)
Re: What are the last two digits (at ten's place and unit’s place) in the  [#permalink]

### Show Tags

24 Oct 2017, 06:36
chetan2u wrote:
nkmungila wrote:
What are the last two digits (at ten's place and unit’s place) in the numerical value of the following product?

243 x 5787 x 5315 x 7779 x 8262 x 3179 x 993.

A. 10
B. 30
C. 50
D. 70
E. 90

hi..

we have numbers with 2 and 5, so UNIT's place is surely 0..
here we have to find the tens digit too..

this will be given by $$5315*8262..... 15*2=30$$

rest all numbers we require to concentrate on only the UNITs digit
$$243 * 5787 * 7779 * 3179 * 993.......3*7*9*9*3....21*81*3......1*1*3=3$$

so LAST two digits are 30*3=90

E

HI chetan2u

Can you please explain why are we multiplying 30*3 here?

Is it not we just multiply 3*7*9*9*3*10?
_________________

आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution

Math Expert
Joined: 02 Aug 2009
Posts: 7107
What are the last two digits (at ten's place and unit’s place) in the  [#permalink]

### Show Tags

24 Oct 2017, 07:15
1
NandishSS wrote:
chetan2u wrote:
nkmungila wrote:
What are the last two digits (at ten's place and unit’s place) in the numerical value of the following product?

243 x 5787 x 5315 x 7779 x 8262 x 3179 x 993.

A. 10
B. 30
C. 50
D. 70
E. 90

hi..

we have numbers with 2 and 5, so UNIT's place is surely 0..
here we have to find the tens digit too..

this will be given by $$5315*8262..... 15*2=30$$

rest all numbers we require to concentrate on only the UNITs digit
$$243 * 5787 * 7779 * 3179 * 993.......3*7*9*9*3....21*81*3......1*1*3=3$$

so LAST two digits are 30*3=90

E

HI chetan2u

Can you please explain why are we multiplying 30*3 here?

Is it not we just multiply 3*7*9*9*3*10?

Hi..
2 and 5 give us the last digit 0, and th esecond last will be given by the remaining last digit incl the second last of terms giving 0..

LOOK it this way..

$$243 * 5787 * 5315 * 7779 * 8262 * 3179 * 993 = 243 * 5787 * \frac{5315}{5} * 5 * 7779 * \frac{8262}{2} * 2 * 3179 * 993 =243 * 5787 * 1063 * 7779 * 4131 * 3179 * 993 *10$$...
now take units digit... $$3*7*3*9*1*9*3*10=90$$
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor

Director
Joined: 06 Jan 2015
Posts: 529
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)
Re: What are the last two digits (at ten's place and unit’s place) in the  [#permalink]

### Show Tags

24 Oct 2017, 07:37
chetan2u This sounds good thanks a lot now I got it.
_________________

आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution

Re: What are the last two digits (at ten's place and unit’s place) in the &nbs [#permalink] 24 Oct 2017, 07:37
Display posts from previous: Sort by

# What are the last two digits (at ten's place and unit’s place) in the

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.