Question

very urgent ................................... please give answer of this question.
1. The sum of two digits of a number is 9 .If 9 is subtracted from the number then the digits are reversed. what is the number?
2. If 2x+y=5 then 4x+2y=?
3. In a 100 meters race , A can beat B by 25 m and B can beat C by 4 m .In the same race ,A can beat C by?
4. If 17xy+7=19xy then, 4xy=?
5. How many 3's are there in the following sequence which are neither preceded by 6 nor immediately followed by 9?
9 3 6 6 3 9 5 9 3 7 8 9 1 6 3 9 6 3 9

Answer 1

1. Let the no. at ones place = x
Let the no. at tens place = 9-x
Original no. = 10(9-x)+x
= 90-10x+x
= 90-9x
When the digits are reversed,
No. at ones place = 9-x
No. at tens place = x
New no. = 10(x)+9-x
= 10x+9-x
= 9x+9
A/Q 90-9x - 9 = 9x+9
9x+9x = 90-9-9
18x = 72
x = 4
No. at ones place = x = 4
No. at tens place = 9-x = 5
∴ Original no. = 54

2. 2x+y = 5
    2(2x+y) = 2(5)
    4x+2y = 10 

3. Since A beats B by 25 m,
A = B+25 (i)
Since B beats C by 4 m,
B = C+4 (ii)
Putting the value of B in Eq.(i), we get,
A = B+25
A = (C+4) + 25
A = C+29
∴ A beats C by 29 m,

4. 17xy+7 = 19xy
2xy = 7
xy = 3.5
Now, 4xy = 4 x 3.5 = 14

5. The 1st & 3rd 3 are neither preceded by 6 nor immediately followed by 9.