Please help me with my math problems

Ican figure out 20 shares multiply by $117.98 =2359.6920 shares multiply by $124.32=2486.40then take 40 shares multiply by $128.48=5139.20after that i'm lost any be greatly appreciated.

If the measure of xyz is 81 what is the measure of yz

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?