Suppose the digit at unit's places is y and that at ten's places is x.Then, the number = 10x + y,According to the question.x + y = 8 .......(i)Again 10x + y - 18= 10y + x= 10x + y - 10y - x = 18= x - y = 2 ............(iii)From, equation (i) and (iii) we get x + y = 8x - y = 22x = 10= x = 5 and y = 3∴ number = 10 x 5 + 3 = 53
Let the numbers be x, x + 2, x + 4, x + 6, and x + 8Avg = x + x + 2 + x + 4 + x + 6 + x + 8/5 = 40Therefore, 5x + 20 = 200Therefore, x = 180/5 = 36Therefore, r = x + 4 = 40 s = x + 6 = 42Therefore, Product = 1680
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