The height of the tallest doll = 12 inches
The height of 2nd doll = 12×7/10
The height of 3rd doll = 12×7/10×7/10 = 12×(7/10)²
The height of 4th doll = 12×7/10×7/10×7/10 = 12×(7/10)³
Therefore the height of the smallest doll = 12×[tex]7/10^{(n-1)}[/tex]
where n is the number of dolls
So, if there are 5 dolls then the height of the smallest doll will be
12×[tex]7/10^{(5-1)}[/tex] = 12×[tex]7/10^{4}[/tex] = 2.8812 inches
