18 . scumpire 1,2 + 1,2 ·40/100=1,2 + 1,2·2/5=1,2( 1+2/5)= 1,2 ·7/5=1,68lei
19 . 15lei .................10 agende ..............150lei
reducere 150 - 10%·150= 150 - 15=135
o agenda costa 135: 10 = 13,5 lei
20. dobinda = suma ·p% ·numarul de ani = 3.000000· 16/100 · 1=480000
suma totala = 3000000 + 480000= 3480000lei
22. 8% dinx = 32 8x / 100 =32 x=400
24.x .....................100 %
6lei.....................5% 5·x=6·100 x=120
ieftinit 120 -6 =114 lei
