Advertisements
Advertisements
प्रश्न
In a two-digit number, the sum of the digits is 7. The difference of the number obtained by reversing the digits and the number itself is 9. Find the number.
Advertisements
उत्तर
Let x be the digit at ten's place and y be the digit at unit's place.
Then, the number is 10x + y.
Number obtained by reversing the digits = 10y + x
According to given information, we have
x + y = 7 ....(i)
And, (10y + x) - (10x + y) = 9
⇒ 10y + x - 10x - y = 9
⇒ 9y - 9x = 9
⇒ 9(y - x) = 9
⇒ y - x = 1 ....(ii)
Adding eqns. (i) and (ii), we get
2y = 8
⇒ y = 4
⇒x + 4 = 7
⇒x = 3
∴ Required number
= 10x + y
= 10 x 3 + 4
= 30 + 4
= 34.
APPEARS IN
संबंधित प्रश्न
Solve for x and y:
4x = 17 - `[ x - y ]/8`
2y + x = 2 + `[ 5y + 2 ]/3`
10% of x + 20% of y = 24
3x - y = 20
Solve the following simultaneous equation :
8v - 3u = 5uv
6v - 5u = -2uv
Solve the following pairs of equations:
`(3)/(2x) + (2)/(3y)` = 5
`(5)/x - (3)/y` = 1
Can the following equations hold simultaneously?
7y - 3x = 7
5y - 11x = 87
5x + 4y = 43
If yes, find the value of x and y.
If the following three equations hold simultaneously for x and y, find the value of 'm'.
2x + 3y + 6 = 0
4x - 3y - 8 = 0
x + my - 1 = 0
Salman and Kirti start at the same time from two places 28 km apart. If they walk in the same direction, Salman overtakes Kirti in 28 hours but if they walk in the opposite directions, they meet in 4 hours. Find their speeds (in km/h).
9 pens and 5 pencils cost Rs.32, and 7 pens and 8 pencils cost Rs.29. Find the unit price for each pen and pencil.
Sunil and Kafeel both have some oranges. If Sunil gives 2 oranges to Kafeel, then Kafeel will have thrice as many as Sunil. And if Kafeel gives 2 oranges to Sunil, then they will have the same numbers of oranges. How many oranges does each have?
A and B can build a wall in `6(2)/(3)` days. If A's one day work is `1(1)/(4)` of one day work of B, find in 4 how many days A and B alone can build the wall.
