Question 7

How many numbers greater than 0 and less than a million can be formed with the digits 0, 7 and 8?

Solution

According to given condiitons, numberĀ of 1 digit nos. = 2, numberĀ of 2 digit nos. = 2*3 , numberĀ of 3 digit nos. = $$2*3^2$$ , numberĀ of 4 digit nos. = $$2*3^3$$ , numberĀ of 5 digit numbers. = $$2*3^4$$,Ā Ā NumberĀ of 6 digit nos. = $$2 *3^5$$.

Total summation 2*(1+3+9+27+81+243) = 728 .Ā 


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