Total no.of 3-digit even numbers > 700 works to 149.So option 1 and 2 are ruled out.
first digit can take values - 7,8,9
Last digit can take values - 2,4,6,8
second digit can take values - 1-9 but when the first digit is 7 it can't take the value of 7 and it can't take the value of 2 when the last digit is 2.so the total no.of values the second digit can take is 7.
So total no.of combination works to 3*7*4 = 8
Am I missing any number?
3 digit integers greater than 700
1st place can be filled in 3 ways: 7, 8 or 9
2nd place can be filled in 9 ways: 1-9
3rd place can be filled in 9 ways: 1-9
Total possible numbers: 3*9*9=243
Answer is B.
What is the OA?
the question talks about EVEN integers...
Answer is E.
What is the OA?
dunno OA.. as mentioned with the question.. BTW I also got the same answer 😉
3 digit integers greater than 700
1st place can be filled in 3 ways: 7, 8 or 9
2nd place can be filled in 9 ways: 1-9
3rd place can be filled in 9 ways: 1-9
Total possible numbers: 3*9*9=243
Answer is B.
What is the OA?
How could I miss that? Answer will be C: 108, as 3rd place can be filled in 4 ways only as its and even integer.
srworld SaysMy answer is C.
Share explanation.. if possible..
the first digit can take three values-7,8,9
the second digit can take 9 values-1,2,3,4,5,6,7,8,9
the third digit can take four values-2,4,6,8
so total combinations=3*9*4=108
The q states to have non-zero and distinct digits.Will the above calculation results in same digits as 772 or 788 etc?
Total no.of 3-digit even numbers > 700 works to 149.So option 1 and 2 are ruled out.
first digit can take values - 7,8,9
Last digit can take values - 2,4,6,8
second digit can take values - 1-9 but when the first digit is 7 it can't take the value of 7 and it can't take the value of 2 when the last digit is 2.so the total no.of values the second digit can take is 7.
So total no.of combination works to 3*7*4 = 8
Am I missing any number?
I think as per the ques, 744, 866, 888 etc are also invalid.. I think u forgot to cover those numbers..
Total no.of 3-digit even numbers > 700 works to 149.So option 1 and 2 are ruled out.
first digit can take values - 7,8,9
Last digit can take values - 2,4,6,8
second digit can take values - 1-9 but when the first digit is 7 it can't take the value of 7 and it can't take the value of 2 when the last digit is 2.so the total no.of values the second digit can take is 7.
So total no.of combination works to 3*7*4 = 8
Am I missing any number?
can yoou explain ur answer?
guy with guts Sayscan yoou explain ur answer?
The q talks about distinct and non-zero digits of the even nos > 700.So the number of digits in the second place (hundredth place ) will be 7(should not include the digits in units and thousandth place) and not nine.So the total combination works to 84.
nuttyvarun SaysI think as per the ques, 744, 866, 888 etc are also invalid.. I think u forgot to cover those numbers..
The q states to have non-zero and distinct digits.So 744 can't be possible here..
deepakraam SaysThe q talks about distinct and non-zero digits of the even nos > 700.So the number of digits in the second place (hundredth place ) will be 7(should not include the digits in units and thousandth place) and not nine.So the total combination works to 84.
I simply missed the distinct part.
when first digit is-7 then for different second digits the total number possible is
for digit1-4,2-3,3-4 and so on,total-27
similiarly for 9-27
and for 8-28
total=27+27+28=82
How many even, three digit integers greater than 700 with distinct, non- zero digits are there?
(A) 729
(B) 243
(C) 108
(D) 88
(E) 77
How to solve this in quick time.. ;)
Hi,
A number starting with 7 can have the following ways:
Units' place can be one from 2,4,6,8.
Ten's place can be from 1 to 9 minus numbers selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.4 = 28.
A number starting with 8 can have the following ways:
Units' place can be one from 2,4,6.
Ten's place can be from 1 to 9 minus 1 selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.3 = 21.
A number starting with 9 can have the following ways:
Units' place can be one from 2,4,6,8.
Ten's place can be from 1 to 9 minus 1 selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.4 = 28.
So total numbers would be 28 + 21 + 28 = 77.
Hi,
A number starting with 7 can have the following ways:
Units' place can be one from 2,4,6,8.
Ten's place can be from 1 to 9 minus numbers selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.4 = 28.
A number starting with 8 can have the following ways:
Units' place can be one from 2,4,6.
Ten's place can be from 1 to 9 minus 1 selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.3 = 21.
A number starting with 9 can have the following ways:
Units' place can be one from 2,4,6,8.
Ten's place can be from 1 to 9 minus 1 selected for the units place and hundered's place.
so total numbers starting with 7 will be 7.4 = 28.
So total numbers would be 28 + 21 + 28 = 77.
right answer.i also worked on same line but miscalculated the numbers.
srworld SaysMy answer is C.
3 blue, 2 red and 2 black stripes
Total arrangements: 7!
But the same color stripes are identical.
So possible arrangements: 7! / (3! 2! 2!) = 210
Answer C
How many even, three digit integers greater than 700 with distinct, non- zero digits are there?
(A) 729
(B) 243
(C) 108
(D) 88
(E) 77
How to solve this in quick time.. ;)
For 7XX --> 1*7*4 = 28
For 8XX --> 1*7*3 = 21
For 9XX --> 1*7*4 = 28
___
77 three digit nos poss ..Ans E ...
For 7XX --> 1*7*4 = 28
For 8XX --> 1*7*3 = 21
For 9XX --> 1*7*4 = 28
___
77 three digit nos poss ..Ans E ...
Bhavin as always.. succinct and prcise. thanks man!!
Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
A. 4
B. 6
C. 8
D. 10
E. 12
Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
A. 4
B. 6
C. 8
D. 10
E. 12
Let the two machine rates are x and y and let it takes machine y T days to produce W.
framing equations-
Ty=(T+2)x=W=>w=2xy/(x-y)------1
from second condition-3(x+y)=5/4W......2
solving the above two equations-we get
6x^2-5xy-6y^2=0,solving will give 2x=3y
substitute the value of y in eq-2,
x=w/4
hence if it takes t days to make 2w,tx=2w=t*w/4=2w=>t=8 days
:banghead:
The OA is not matching with my understanding of SD.. plz share your thoughts..
===
70, 75, 80, 85, 90, 105, 105, 130, 130, 130
the list shown consists of times, in seconds, that it took 10 schoolchildren to run a distance of 400 meters. if the standard deviation of the 10 running times is 22.4 seconds, rounded to the nearest tenth of a second, how many of the 10 running times are more than 1 standard deviation below the mean of the 10 running times?
answer choices:
a. 1
b. 2
c. 3
d. 4
e. 5
Sum of all the running times = 1000
Mean of the 10 running times = 100
1 SD = (100-22.4) to (100+22.4) = 77.6 to 122.4
Ques:
How many of the 10 running times are more than 1 standard deviation below the mean of the 10 running times
the answer must be below mean and more than the SD, i.e. between 77.6 and 100.
thus, 80 - 85 - 90 = the 3 running times that satisfy the ques..
answer must be option C. same as OA ;)
thanks all.. I did not get the question in one go.. had to re-read it to solve it..
:banghead:
The OA is not matching with my understanding of SD.. plz share your thoughts..
===
70, 75, 80, 85, 90, 105, 105, 130, 130, 130
the list shown consists of times, in seconds, that it took 10 schoolchildren to run a distance of 400 meters. if the standard deviation of the 10 running times is 22.4 seconds, rounded to the nearest tenth of a second, how many of the 10 running times are more than 1 standard deviation below the mean of the 10 running times?
answer choices:
a. 1
b. 2
c. 3
d. 4
e. 5