Question

Dupa doua reduceri consecutive perima cu 5% iar a doua 10% un telefon costa 855lei , care a fost pretul initial?

Answer 1

Fie x pretul initial;
atunci

x*(95/100)*(90/100)=855
x*(19/20)*(9/10)=855
x*19*9=855*200 |:9
x*19=95*200 |:19
x=5*200
x=1000