Click to Chat

1800-2000-838

+91-120-4616500

CART 0

• 0

MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 600 off
USE CODE: chait6

```
an n digit no is apositive no. with exactly n digit . Nine hundred distinct n digit no. r to be formed using only 3 digit 5,7.9. The smallest value of n is
there r 4 balls of different clolur and 4 boxes colour same as those of balls the no of ways in which the ballon each  1 box could be plkaced such that any ball dosenot go to the box of its own colour

```

6 years ago

Share

```										Hi Anita Sharma!!!
explanation-u have the digits 5,7,9.and u have to form 900 distinct numbers.For any n digit number,the possible ways of filling each digit{that is units,tens,hundreds,etc} is 3
for a 1 digit number,total no. of ways is 3 power1=3{5,7,9}
for a 2 digit number,total no. of ways is 3 power 2+9{55,57,59,75,77,79,95,97,99}
for an n digit number,total no. of ways is 3 power n
now,we hav total no. of ways is 900,so we have to find a minimum n for which 3 power n is greater dan or equal to 900
3 power 6 is 729 and 3 power 7 is 2187,hence 7 is the answer
now the second ques
this is called dearrangements,and der is a forumla given in Dasgupta{which i dont remember now :(}
but,there is an alternative way,where u could choose cases where all 4 go to the ryt boxes,any 3,any2 and any 1 go into the right boxes and subtract the sum of all these cases from 4! which is the total no. of ways of arranging the balls{NOTE-THIS IS POSSIBLE ONLY ID THE NO. IS SMALL,LIKE 4 HERE,U CANT WASTE TYM TRYING TO SORT OUT CASES IF THE NO. OF BALLS/BOCES IS HIGH LIKE 7 OR 8,SO TRY TO CHECK THE FORMULA FOR DEARRANGEMENTS}
No. of ways off all balls goin into the ryt boxes is 1
No. of ways of any 3 balls going into the right boxes is zero as if 3 go into the right boxes,then the 4th will have to go into the right one
No. of ways of any 2 balls goin into the ryt box is 4c2 * 1! = 6*1=6{i.e; choosin 2 go into the ryt ones,and the total ways others go into the wrong ones,which is (2-1)!}
No. of ways of any 1 ball going into the ryt box is 4c1 * 2! =8
now,the sum of all these is 1+0+6+8=15
total ways of arranging is 4!=24
so,total ways of all balls going into the wrong boxes is 24-15 =9
Hope u understand the solutions
If u dont,feel free to call me on 07209736303
ALL THE BEST
PLZZZ APPROVE MY ANSWER IF U LIKE IT
```
6 years ago

Other Related Questions on Trigonometry

sin^2 6°-sin^2 12°+sin^2 18°-sin^2 24°......15 solve it Urgent

Ajay, the complete qution isSolution is sin^2 6°-sin^2 12°+sin^2 18°-sin^2 24°..... upto 15 terms. sin 78°=0 sin 42°+sin 54°+ sin 66°+ + sin 18° sin 6°+ where )=0.5 (your required answer),...

 Kumar 3 months ago

Not any people get my answer why. You can no give answer my question I am join this site

 Vivek kumar 5 months ago

Hello If you want to get the solution quick you should post your question in clear manner. Its not clear what you wnat us to solve, and what does 15 at the end of question means?

 Ajay 5 months ago
Solve: (sin theta+cosec theta)^2 + (cos theta +sec theta)^2- (tan^2 theta + cot ^2 theta)^2

What needs to be solved here ? The question is incomplete....................................................................

 Ajay 6 months ago

i don’t know how to do this...............................................................................................

 Saravanan 2 months ago

this is the question :: Solve: (sin theta+cosec theta)^2 + (cos theta +sec theta)^2 - (tan^2 theta + cot ^2 theta)

 Naveen Shankar 6 months ago
solutions to Question no. 17,18 19 and 20 pleaseeeeeeeeeee

Let the feet of the altitudes on BC, AC, AB, be D,E,F resp. Let the orthocenter be H. The following can be proved easily: ​1. HDCE and HFBD are cyclic quadrilaterals. Then chord HE subtends...

 mycroft holmes one month ago

Draw which is Isoceles as OB = OC. Now which means . Let D, be the foot of the perp from O on BC ( which is also the midpoint of BC). Then OD = OC sin (OBC) = R cos A. Hence the required...

 mycroft holmes one month ago

a cos A = b cos B 2R sin A cos A = 2R sin B cos B sin 2A = sin 2B Either A = B (isoceles or equilateral) or 2A = 180 o – 2B so that A+B = 90 o .(Right-angled)

 mycroft holmes one month ago
If alpha is a real root of the equation ax 2 +bx+c and beta is a real root of equation -ax 2 +bx+c. Show that there exists a root gama of the equation (a/2)x 2 +bx+c which lies between alpha...

 Ajay 6 months ago

Small Mistake in last para posting again..............................................................................................................

 Ajay 6 months ago

We have Similarly, So if P(x) = a/2 x 2 +bx +c, then and are off opposite sign and hence there must exist a root between the two numbers.

 mycroft holmes 6 months ago
In the listed image can you tell me how beta*gamma = 2 ….. . . .. ??

The value of gamma is still not correct, either printing mistake or you gave me wrong value. The correct value of gamma is below

 Ajay 5 months ago

Thankyou so much............................. …......................................................................!

 Anshuman Mohanty 5 months ago

Yes sorry..... . . . .it is not so clear.. ok the values are beta = α + α^2 + α^4 and gamma = α^3 + α^5 + α^7

 Anshuman Mohanty 5 months ago
if |z - i| Options: a*) 14 b) 2 c) 28 d) None of the above

If |z-i| = ?? PLs complete the question

 Nishant Vora one month ago

Got it! [z + 12 – 6 i ] can be rewritten as [ z – i + 12 – 5 i] => | z – i | and => |12 – 5 i | = sqrt ( 12^2 + 5^2) = 13......................(2) => | z + 12 – 6 i | => | z + 12 – 6 i |...

 Divya one month ago

I tried posting the question several times, it kept cutting off the rest of the question. Here: If | z-1| Options: a*) 14 b) 2 c) 28 d) None of the above

 Divya one month ago
View all Questions »

• Complete JEE Main/Advanced Course and Test Series
• OFFERED PRICE: R 15,000
• View Details
Get extra R 6,000 off
USE CODE: chait6

Get extra R 600 off
USE CODE: chait6

More Questions On Trigonometry