how to solve this using the for loop and if

the price, in dollars, of a certain stock over a 10 day period is given in following array.

price=[19,18,22,21,25,19,17,21,27,29]
suppose you owned 1000 shares at the start of the 10 day period, and you bought 100 shares everyday the price was below $20 and sold 100 shares every day the price was above $25.
compute:
1-the amount you spent in buying share
2-the amount you received in selling shares
3-total number of shares you own after the 10th day
4-the net increase in the worth of your portfolio

x=[19,18,22,21,25,19,17,21,27,29]
p=0;
for i=1:10;
      if x(i)<20;
      p=p+(100*(x(i)));

       end       
U=sum(p)
end

k=0;
for i=1:10;
if x(i)>25
  k=k+(100*x(i))
end
end

total=1000

[Walter Roberson]

What problem are you observing?

Why are you overwriting "U" during each iteration of the first "for" loop ?