The sum of the digits of a two-digit number is 11. If the digits are reversed, the new number is 27 more than the original number. What is the original number?
47
Let the tens digit be x and units digit be y, with \(x+y=11\).
Reversed number minus original: \((10y+x)-(10x+y) = 27 \Rightarrow 9y-9x=27 \Rightarrow y-x=3\).
Solving \(x+y=11\) and \(y-x=3\): \(y=7,\ x=4\).
Original number: \(10\times4+7 = 47\).
Hence, the original number is 47.
If $2x - 3y = -1$ and $\frac{x}{x+y} = \frac{7}{12}$, then the value of $2xy$ is:
What is the solution of the following equations ?
2x + 3y = 12 and 3x − 2y = 5
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If 8k 6+ 15k 3– 2 = 0, then the positive value of \(\left( {{\rm{k}}\,{\rm{ + }}\,\frac{1}{{\rm{k}}}} \right)\) is :