Question

IN opt plase ,una neagra si sapte albe ,se afla 189 mingi de tenis.IN plsa neagra si in prima plasa alba se afla acelasi nr.de mingi.
Afla cate mingi se afla in fiecare plsa daca numarul mingilor din plasele albe sunt nr. consecutive

Answer 1

fie n=plasa neagra si a, b, c, d, e, f, g  plasele albe
n+a+b+c+d+e+f+g=189
n=a
b=a+1
c=a+2
d=a+3
e=a+4
f=a+5
g=a+6
a+a+a+1+a+2+a+3+a+4+a+5+a+6=189
8a+21=189
8a=189-21
8a=168
a=168:8
a=21
n=21
b=22, c=23, d=24, e=25, f=26, g=27