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If a computer program generates threedigit odd numbers using the numb [#permalink]
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07 Apr 2016, 08:41
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Re: If a computer program generates threedigit odd numbers using the numb [#permalink]
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07 Apr 2016, 20:23
Bunuel wrote: If a computer program generates threedigit odd numbers using the numbers 9, 7, 0, 4, and 1, and the digits can be repeated, what is the probability that the number formed from the program is a multiple of three?
A. 1/2 B. 1/3 C. 1/5 D. 1/6 E. 1/7 The Q is not where the answer can be found straightway.. Key words you should look into.. 1)If a computer program generates threedigit odd numbers using the numbers 9, 7, 0, 4, and 1 This means that we have to take total ways as possible 3digit ODD numbers only and NOT all possible 3  digit numbers
2) Digits can be repeated..Lets solve 1) Lets first find TOTAL ways..a) first/leftmost digit can be any of 5 except 0, so 4 ways b) middle digit can be any of the 5. so 5 ways c) the units digit can be ONLY odd 1,7, and 9 so 3 waysTOTAL = 4*5*3=60 ways 2) lets now find multiple of 3..a) Digits not div by 37,4 and 1 will each leave remainder of 1 so they can be grouped together to form multiples of 3.. first place  3 ways, second digit  3 ways, and units digit ONLY 1 and 7  2ways Total ways = 3*3*2=18 b) digits div by 39 and 0 No other digit can be used along with them as no other pair gives us sum of remainder as 3.. first place  1 way, second digit  2 ways, and units digit ONLY 9  1 way Total ways = 1*2*1=2 TOTAL= 2+18=20 Prob =\(\frac{20}{60} =\frac{1}{3}\) B
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Re: If a computer program generates threedigit odd numbers using the numb [#permalink]
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29 Apr 2017, 17:01
do you know any kind of similar problem



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Re: If a computer program generates threedigit odd numbers using the numb [#permalink]
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30 Apr 2017, 03:33



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If a computer program generates threedigit odd numbers using the numb [#permalink]
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30 Apr 2017, 08:52
Bunuel wrote: If a computer program generates threedigit odd numbers using the numbers 9, 7, 0, 4, and 1, and the digits can be repeated, what is the probability that the number formed from the program is a multiple of three?
A. 1/2 B. 1/3 C. 1/5 D. 1/6 E. 1/7 I couldn't understand how to find 3 digit numbers, which is multiple of 3. Bunuel/Karishma could you help me ? Regards, Ammu



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Re: If a computer program generates threedigit odd numbers using the numb [#permalink]
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30 Apr 2017, 10:07
ammuseeru wrote: Bunuel wrote: If a computer program generates threedigit odd numbers using the numbers 9, 7, 0, 4, and 1, and the digits can be repeated, what is the probability that the number formed from the program is a multiple of three?
A. 1/2 B. 1/3 C. 1/5 D. 1/6 E. 1/7 I couldn't understand how to find 3 digit numbers, which is multiple of 3. Bunuel/Karishma could you help me ? Regards, Ammu Hey Ammu,
• To find multiples of 3, you need to know the divisibility property of 3.
• So suppose ABC is a three digit number.
• To check if the number of divisible by three, we just need to add the digits and divide it by 3.
• So if (A+B+C) is divisible by 3, the number ABC is divisible by 3.
o Now we have the digits: 9,7,0,4,1 o So, we need to choose 3 digits, the sum of which is divisible by 3,
If we take say 9,7,0 This gives us 9 + 7 + 0 = 16 which is not divisible by 3. o But, if we consider 7,4,1 : 7 +4 +1 = 12 and 12 is divisible by three.
Hence any number which is formed from the three digits 7,4 and 1 will be divisible by 3. The total three digit numbers which can be formed from these digits(7,4,1) = 3*3*2 = 18 Notice that the last place can be filled only in 2 ways (7 and 1), since we want only ODD numbers. o As there are no other possible 3 digits using which can form a three digit number divisible by three We can conclude that there are only 18 possible multiples of 3. • Note: If you want to figure out which digits to choose whose sum will be multiple of 3, kindly refer to chetan2u post, he has given a great explanation for that. Thanks, Saquib Quant Expert eGMATRegister for our Free Session on Number Properties (held every 3rd week) to solve exciting 700+ Level Questions in a classroom environment under the realtime guidance of our Experts
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Re: If a computer program generates threedigit odd numbers using the numb [#permalink]
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30 Apr 2017, 10:55
EgmatQuantExpert wrote: ammuseeru wrote: Bunuel wrote: If a computer program generates threedigit odd numbers using the numbers 9, 7, 0, 4, and 1, and the digits can be repeated, what is the probability that the number formed from the program is a multiple of three?
A. 1/2 B. 1/3 C. 1/5 D. 1/6 E. 1/7 I couldn't understand how to find 3 digit numbers, which is multiple of 3. Bunuel/Karishma could you help me ? Regards, Ammu Hey Ammu,
• To find multiples of 3, you need to know the divisibility property of 3.
• So suppose ABC is a three digit number.
• To check if the number of divisible by three, we just need to add the digits and divide it by 3.
• So if (A+B+C) is divisible by 3, the number ABC is divisible by 3.
o Now we have the digits: 9,7,0,4,1 o So, we need to choose 3 digits, the sum of which is divisible by 3,
If we take say 9,7,0 This gives us 9 + 7 + 0 = 16 which is not divisible by 3. o But, if we consider 7,4,1 : 7 +4 +1 = 12 and 12 is divisible by three.
Hence any number which is formed from the three digits 7,4 and 1 will be divisible by 3. The total three digit numbers which can be formed from these digits(7,4,1) = 3*3*2 = 18 Notice that the last place can be filled only in 2 ways (7 and 1), since we want only ODD numbers. o As there are no other possible 3 digits using which can form a three digit number divisible by three We can conclude that there are only 18 possible multiples of 3. • Note: If you want to figure out which digits to choose whose sum will be multiple of 3, kindly refer to chetan2u post, he has given a great explanation for that. Thanks, Saquib Quant Expert eGMATRegister for our Free Session on Number Properties (held every 3rd week) to solve exciting 700+ Level Questions in a classroom environment under the realtime guidance of our Experts I got it. Thank You for explanation. Regards, Ammu




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