Question

doua carti costau impreuna 60000 lei . Stiind ca pretul unei s-a redus cu 10 % , iar celeilalte cu 15b % si dupa reducere costa impreuna 52800 lei , sa se afle          cat costa , dupa reducere, fiecare carte

Answer 1

Notam cartile cu A si B:

A+B=60000
(A-A*10/100) +(B-B*15/100)=52800
A+B-A*10/100 -B*15/100=52800
=> 60000- A*10/100 -B*15/100=52800
A*10/100 +B*15/10=60000- 52800=7200
=> 10*A+15*B=720000

Si avem:
 A+B=60000       |*10 =>

10A+10B=600000
10A+15B=720000

LE SCADEM (a doua minus prima) :

10*A+15*B-10*A-10*B=720000-600000=120000

=> 5*B=120000
B=24000
A=60000-24000= 36 000

DUPA REDUCERE CARTILE COSTA:

A->   36000-36000*10/100 =32400
B->  24000-24000*15/100 =20400

Proba:32400+20400=52800