Question

Bianca rezolva in fiecare zi cu 2 probleme mai mult decat in ziua precedenta ,astfel reuseste sa rezolve in 6 zile 48 de probleme pe care le-a avut in vacanta .Cate probleme a rezolvat ia a 4-a zi?
URGENT!!

Answer 1

a=probleme in prima zi
b=in a doua zi
c=in a treia zi
d=in a patra zi
e=in a cincea zi
f=in a sasea zi


a+b+c+d+e+f=48
b=a+2
c=b+2=a+2+2=a+4
d=c+2=a+4+2=a+6
e=d+2=a+6+2=a+8
f=e+2=a+8+2=a+10

a+a+2+a+4+a+6+a+8+a+10=48
6a+30=48
6a=48-30
6a=18
a=18:6
a=3 probleme in prima zi

d=a+6=3+6=18 probleme a rezolvat in a patra zi