Two-digit number

In a two-digit number, the number of tens is three greater than the number of units. If we multiply the original number by a number written in the same digits but in reverse order, we get product 3 478. Find the original number.

Correct answer:

x =  74

Step-by-step explanation:

$$\begin{gathered} a=3+b \\ (10\cdot a+b)\cdot (10\cdot b+a)=3478 \\ 3478=2\times 37\times 47 \\ 47\cdot 74=3478 \\ x=74 \end{gathered}$$

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