A two-digit number is such that four times the sum of its digits is equal to the number formed by reversing its digits. If the difference between the digits is 3, find the original number.
63
Let the tens digit be x and units digit be y. The condition gives \(4(x+y) = 10y+x\) (the reversed number).
Simplifying: \(4x+4y=10y+x \Rightarrow 3x=6y \Rightarrow x=2y\).
With \(x-y=3\) and \(x=2y\): \(2y-y=3 \Rightarrow y=3,\ x=6\).
Original number: \(10x+y = 63\).
Hence, the original number is 63.
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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When 5 children from class A join class B, the number of children in both classes is the same. If 25 children from B, join A, then the number of children in A becomes double the number of children in B. The ratio of the number of children in A to those in B is:
If (x + 6y) = 8, and xy = 2, where x > 0, what is the value of (x 3+ 216y 3)?
If 8k 6+ 15k 3– 2 = 0, then the positive value of \(\left( {{\rm{k}}\,{\rm{ + }}\,\frac{1}{{\rm{k}}}} \right)\) is :