Z6 – I – 6 MO 2019

Mother studied multi-digit numbers in which odd and even digits regularly alternate. Those that start with an odd digit she called comical and those that start with an even digit she called cheerful. (E.g. The number 32387 is comical, the number 4529 is cheerful. )

Among the three-digit numbers, determine whether there is more comical or cheerful, and by how much.

Correct answer:

n =  25

Step-by-step explanation:

$$\begin{gathered} p:0,2,4,6,8 \\ n:1,3,5,7,9 \\ m(p)=5 \\ m(n)=5 \\ k=5\cdot 5\cdot 5=125 \\ v=4\cdot 5\cdot 5=100 \\ k>v \\ n=k-v=125-100=25 \end{gathered}$$

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