if a number is choosen between 100 and 999 includeing these
numberrs what is the provbabilty that the number selected
does not contain a 7 is
Answers were Sorted based on User's Feedback
Answer / jamesk
p = prob(1st digit not 7)*prob(2nd digit not 7)*prob(3rd
digit not 7)
=(8/9)*(9/10)*(9/10)
=0.72
Sandhya had it right except that there are 900 numbers
between 100 and 999 inclusive (not 899).
| Is This Answer Correct ? | 59 Yes | 6 No |
Answer / seiko
no 0f 7's in 100 to 200 is
107,117,127,137,147,157,167,170,171,172,173,174,175,176,177,
178,179,187,197.
so total of 19 numbers between 100 and 199
repeat that for 200-299, 300-399,...,600-699, 800-899, 900-
999, we have 19*8 = 152 occurences
for 700-799, all 100 of them contain a 7
so total numbers contain a 7 is 152 + 100 = 252
total numbers between 100 and 999 is 900
probability = (900-252)/900 = 0.72
| Is This Answer Correct ? | 51 Yes | 8 No |
Answer / ajeet
100-199------19
similarly for all ranges till 999 except for:
700-799----100
total no.containing 7's= 19*8+100=252
Therefore,
probability=(900-252)/900
= 648/900
= 0.72
| Is This Answer Correct ? | 10 Yes | 3 No |
Answer / mayank kumar
total numbers between 100 and 999 =900
number that have a digit 7 between 100 and 199 =19
similarly no. that have digit 7 between 200 and 699=5*19
number that have digit 7 between 700 and 799=100
number that have a digit 7 between 800 and 999 =2*19
so total number that have digit seven in them between 100 and 999 are=8*19+100 =252
so numbers that does not have 7 digit in them =900-252 =648
therefore required prob, p =648/900 = 0.72
| Is This Answer Correct ? | 6 Yes | 3 No |
Answer / shruti
here are 900 numbers between 100 and 999.
those that contain 7 are.....
107, 117, 127, ........ -- 10 of these
207, 217, 227, ........ -- 10 of these too
307, 317, 327, .......
....
9*10 numbers that end in 7.
170, 171, 172, 173, 174, 175, 176, (NOT 177 WE ALREADY COUNTED IT), 178, 179 -- 9 of these
270, 271, 272, 273, 274, 275, 276, (NOT 277 WE ALREADY COUNTED IT), 278, 279 -- 9 of these
...
and so on
so 9*9 numbers that have a middle digit of 7
and finally
700, 701, 702, 703, 704.................., but NOT
(707, 717, 727,....) or (770, 771, 772, 773, ....)
So that's (100 - 10 - 9) = 81 numbers that start with 7.
We had 900 numbers.
N = 900 - 90 - 81 - 81 = 648
So the probability is 648/900 = 0.72
| Is This Answer Correct ? | 5 Yes | 3 No |
While packing some return gifts, a mother decides to put some toffees in each gift packet. If she keeps 5 toffees in each packet, she is left with none. But if she keeps 2, 3 or 4 toffees in a packet, she is left with 1 toffee . What is the minimum number of toffees that she needs?
What do you think is the most fascinating game? Hi, I am a big game fan. Could anyone introduce some fascinating game for me? Thank you!
sir i need rrb secunderabad goodsguard previous exam papers
Could anyone please email the answers to the verizon 2014 aptitude test
Four concentric circles are given. The radius of 1st circle is x. Next is 2x, then 3x and 4x. Given that area between 2nd and 1st is A and 4th and 3rd circles being B. Find ratio of A to B
what do you call a canadian of french descent
Present population of town is 35,000 having males and females. If The population of males is increased by 6% and if the population of females is increased by 4%, then after 1 year the population becomes 36,700. Find the number males and females ?
If P=Total number of components, Q = number of defective components .What is the % of non defective components?
A bag contains 6 black and 8 white balls. One ball is drawn at random. What is the probability that the ball drawn is white?
Number Series 25,25,22,22,19,19,?
There are 150 weights .Some are 1 kg weights and some are 2 kg weights. The sum of the weights is 260.is the number of 1kg weights?
There are 7 people who take a test among which M is the worst, R is disqualified, P and S obtain same marks, T scores less than S and Q scores less than P, N scores higher than every one.