A boy imagined a four digit multiple of 5 with different digits. If the first digit is erased, the obtained number is multiple of

2 thoughts on “A boy imagined a four digit multiple of 5 with different digits. If the first digit is erased, the obtained number is multiple of”

1. A boy imagined a four digit multiple of 5 with different digits. If the first digit is erased, the obtained number is multiple of 9. If the second digit is erased, the obtained number is multiple of 11. If the third digit is erased, the obtained number is multiple of 7. What number a boy imagined?

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2. Step-by-step explanation:

   sin45° × sin30° + cos 45° × cos 30°

   \begin{gathered}( \frac{1}{ \sqrt{2} } \times \frac{1}{2}) + ( \frac{1}{ \sqrt{2} } \times \frac{ \sqrt{3} }{2)} \\ = \frac{1}{2 \sqrt{2} } \times \frac{ \sqrt{3} }{ 2\sqrt{2} } \\ = \frac{(1 + \sqrt{3)} }{2 \sqrt{2} } \end{gathered}

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