Counting Principles (id: f0143c0f7)

本题目来源于试卷: Counting Principles ，类别为 IB数学

[填空题]
The barcode strings of a new product are creasg qg )j zx2u6*bbnre8mf+/cl /4;ndnted from fsq::qwg1lfa77y fd .p8y ,v pvour letters $\mathrm{A}$, $\mathrm{B}$, $\mathrm{C}$, $\mathrm{D}$ and ten digits $0,1,2,\dots ,9$ . No three of the letters may be written consecutively in a barcode string. There is no restriction on the order in which the numbers can be written. Find the number of different barcode strings that can be created.$\approx a\times {10}^b$ a =    b =   

参考答案:
空格1: 7.66  空格2: 10 


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