5000 yuan in the first year, 50% of income18.

5000*( 1+50%) to the power of 18

In the second year, 5000 yuan, the income 17 50%.

5000*( 1+50%) to the power of 17.

.......

/kloc-5,000 in 0/7 years, and the income is 2,50%.

Quadratic of 5000 *( 1+50%)

/kloc-5000 in 0/8 years will earn 1 50%.

5000*( 1+50%) 1 power

In other words, there has always been

5000*( 1.5^ 18+ 1.5^ 17+.......... 1.5^2+ 1.5)

=5000* 1.5*( 1- 1.5^ 18)/( 1- 1.5)

=5000* 1.5*( 1- 1477.89 188)/(-0.5)

=5000* 1.5*( 1477.89 188- 1)/0.5

=5000* 1.5* 1476.89 188*2

= 15000* 1476.89 188

=22 153378.2

Twenty-two million one hundred and fifty-three thousand three hundred and seventy-eight yuan and twenty cents

Children 18 years old will have 22 153378 yuan and 20 points.

This topic is a topic of geometric series.

Need the summation formula of this series.

The sum of the first n terms of geometric series is sn = a1(1-q n)/(1-q) or sn = (a1-an * q)/(1-q) (q ?.

In geometric series, the first term A 1 and the common ratio q are not zero.

Note: in the above formula, a n stands for the n power of a.

Geometric series are often used in life.

For example, banks have a way of paying interest-compound interest.

That is, the interest and principal of the previous period are added together to calculate the principal.

Then calculate the interest of the next period, which is what people usually call rolling interest.

The formula for calculating the sum of principal and interest according to compound interest: sum of principal and interest = principal *( 1+ interest rate) deposit period.

The problem is that every time you deposit 18, you need to calculate the compound interest for 5000 years.