- hi pls help me in solving these problems..1. how many 3 digit no.s r there which when divided by 7 or 8 gives a remainder of 4 in each case?2. what is the sum of all the numbers formed by taking each of the digits 2,3,5,6 and 8 once?3.fresh mango contains 70% water by weight whereas dry mango contains 10% water by weight. what is the weight of dry mango that can b obtained from 20 kg of fresh mango?a. 6.66kgb. 6 kgc. 6.84 kgd. cannot b determined4. starting with 1, positive integers are written one after the other. what is the 40000th digit that will be written?a. 2b. 4c. 3d. 1

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Such a no. will be LCM(7,8)*K + 4 where K is a +ve integer

i.e. 56K + 4

so for 3 digits 1<K<18

16 values of K are possible . Hence 16 such nos.....

Ans 2.

there will be 5*4*3*2*1 = 120 nos. that can be formed with these 5 digits....

lets consider the no. which end with '1'.....

ie. fix '1' at the end so there are 4! such nos.....similarly for 2,3,4,5....

hence the sum of the unit's digits of these nos ....

24*(1+2+3+4+5)

the sum of the ten's digits of these nos ....

24*(1+2+3+4+5)*10

the sum of the hundred's digits of these nos ....

24*(1+2+3+4+5)*100

the sum of the thousand's digits of these nos ....

24*(1+2+3+4+5)*1000

the sum of the ten thousand's digits of these nos ....

24*(1+2+3+4+5)*10000

total sum = 24 * (1+2+3+4+5)* (10000+1000+100+10+1)

= 24 * (1+2+3+4+5)* (11111)

= 24 * (15)* (11111)

= 4! * (15)* (11111)

so, in general , we have a formula for this type of questions ....

ie. SUM = (total digits-1)! * (sum of digits) * (1111.......)

where no. of 1's = total digits

Ans 3.

20 kg of fresh mango ---> 6 Kg net mango :)

so to contain this much net mango

we get to know that 6kg should be 90% of the dry mango...

so .9X = 6

X = 6.66

Ans. 4

m workin on it :)wrote:*shruti bhagi <shruti_bhagi@...>*hi pls help me in solving these problems..1. how many 3 digit no.s r there which when divided by 7 or 8 gives a remainder of 4 in each case?2. what is the sum of all the numbers formed by taking each of the digits 2,3,5,6 and 8 once?3.fresh mango contains 70% water by weight whereas dry mango contains 10% water by weight. what is the weight of dry mango that can b obtained from 20 kg of fresh mango?a. 6.66kgb. 6 kgc. 6.84 kgd. cannot b determined4. starting with 1, positive integers are written one after the other. what is the 40000th digit that will be written?a. 2b. 4c. 3d. 1

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Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1ยข/min. - soln 1---------------------------------------3 digit nos which divided by 7 leaves remainder four is 7x+4 where x=14 to 142 so total (142-14)+1 nos=1293 digit nos which divided by 8 leaves remainder four is 8x+4 where x=12 to 124so total (124-12)+1nos=113so total no of nos is=129+113=242but there r nos that when divided by both 7 n 8 leave reamainder 4. We have counted thse nos twicethese nos rof the form 56x+4 where x=2 to 17 total 17-2+1 nos=16So actual no of 3 digit nos =242-16=226soln 2-------------------------its a very standard problem u can get in any XI th standard maths booksoln 4---------------------------------------Digits contributed by 1 digit nos=1*9Digits contributed by 2 digit nos=2*90Digits contributed by 3 digit nos=3*900....Digits contributed by n digit nos=n*9*10^(n-1)----------------------------------------------------------------Total no of digits= n*10^n- (10^n-1)/9putting n=4we find total no of digits upto all 4 digit nos is 38,889No of digits after 4 digit nos and 40,000 th digit is1111all r contributed by 5 digit nosthere r 200 5 digit nosso 40,000th digit is the staring digit of 10200 i.e 1Ans (d)
wrote:*shruti bhagi <shruti_bhagi@...>*hi pls help me in solving these problems..1. how many 3 digit no.s r there which when divided by 7 or 8 gives a remainder of 4 in each case?2. what is the sum of all the numbers formed by taking each of the digits 2,3,5,6 and 8 once?3.fresh mango contains 70% water by weight whereas dry mango contains 10% water by weight. what is the weight of dry mango that can b obtained from 20 kg of fresh mango?a. 6.66kgb. 6 kgc. 6.84 kgd. cannot b determined4. starting with 1, positive integers are written one after the other. what is the 40000th digit that will be written?a. 2b. 4c. 3d. 1

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there are 16 numbers.

solution:

to find least no. which when divided by 7 and 8 leaves remainder 4 in

each case, find lcm of 7 and 8 and add 4 to it i.e. (lcm of 7 & 8 )+

4.

but we need 3 digit nos.

so lcm of 7 nd 8 is 56. the lowest three digit multiple of 56 is 112

(56*2).

therefore, the first three digit number which gives 4 when divided by

either 7 or 8 is 112+4 i.e. 116.

similarly the highest three digit no. fulfilling the condition would

be the highest three digit multiple of 56 + 4.

the highest three digit no. which is a multiple of 56 is 952 (to find

out divide 1000 by 56 which gives 17.something. so 17*56 will be the

highest three digit multiple of 56.)

so 952+4 = 956 is the highest three digit number fulfilling the

criteria.

therefore by A.P. a+(n-1)d = L

now, L=952

a=116

d=56

hence, n=16.

--- In ascent4cat@yahoogroups.com, shruti bhagi <shruti_bhagi@...>

wrote:>

gives a remainder of 4 in each case?

> hi pls help me in solving these problems..

>

> 1. how many 3 digit no.s r there which when divided by 7 or 8

>

the digits 2,3,5,6 and 8 once?

> 2. what is the sum of all the numbers formed by taking each of

>

contains 10% water by weight. what is the weight of dry mango that

> 3.fresh mango contains 70% water by weight whereas dry mango

can b obtained from 20 kg of fresh mango?> a. 6.66kg

other. what is the 40000th digit that will be written?

> b. 6 kg

> c. 6.84 kg

> d. cannot b determined

>

> 4. starting with 1, positive integers are written one after the

> a. 2

Just radically better.

> b. 4

> c. 3

> d. 1

>

>

> ---------------------------------

> Sneak preview the all-new Yahoo.com. It's not radically different.

>

>

the answer s 1.. coz u see that there are 9 1 digit

> 4. starting with 1, positive integers are written

> one after the other. what is the 40000th digit that

> will be written?

> a. 2

> b. 4

> c. 3

> d. 1

>

numbers and 90 2 digit numbers and 900 three digit

nums.. so keep on going .. ull end up as 1..

hey can anyone tell me how to improve english grammar

and RCS...

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