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media aritmetica a 5 nr consecutive este20 .afla nr?

Răspuns :

( a + a + 1 + a + 2 + a + 3 + a + 4 ) : 5 = 20
(5a + 10) : 5 = 20
5a + 10 = 20 x 5
5a + 10 = 100
5a = 100 - 10
5a = 90
a = 90 : 5
a = 18
b = 19
c = 20
d = 21
e = 22
a+a+1+a+2+a+3+a+4totul supra 5=20
5xa+10=20x5
5xa=100-10
5a=90
a=90:5
a=18
a+1=19
a+2=20
a+3=21
a+4=22