Given initial values:
$X=2,\quad Y=4$
Rule:
$X=\frac{XY}{2}$ and $Y=Y+1$
Now update step by step:
First iteration:
$X=\frac{2\times 4}{2}=4,\quad Y=5$
Second iteration:
$X=\frac{4\times 5}{2}=10,\quad Y=6$
Third iteration:
$X=\frac{10\times 6}{2}=30,\quad Y=7$
Fourth iteration:
$X=\frac{30\times 7}{2}=105,\quad Y=8$
Fifth iteration:
$X=\frac{105\times 8}{2}=420,\quad Y=9$
Sixth iteration:
$X=\frac{420\times 9}{2}=1890,\quad Y=10$
Seventh iteration:
$X=\frac{1890\times 10}{2}=9450$
Now $X=9450$, which is greater than $3000$.
So, the game stops.
Therefore, the final value of $X$ is $9450$.
Let the total bill be Rs $x$.
Amount paid by $9$ people:
$9\times 400=3600$
So, amount paid by the $10^{\text{th}}$ person is:
$x-3600$
Group average is:
$\frac{x}{10}$
According to the question,
$x-3600=\frac{x}{10}+900$
$x-\frac{x}{10}=4500$
$\frac{9x}{10}=4500$
$x=5000$
So, amount paid by the $10^{\text{th}}$ person is:
$x-3600=5000-3600$
$=1400$
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Online Test Series, Information About Examination,
Syllabus, Notification
and More.