Răspuns:
Ma= [tex]\frac{a+b}{2}[/tex]= 6
Mp= [tex]\frac{a*p1+b*p2}{p1+p2}[/tex] p1=3 p2 =7
Mp=5.6 [tex]\frac{3a+7b}{3+7}[/tex] =5.6=>
3a+7b= 5.6x 10 3a+7b= 56
a+b=6x2=12 a+b=12 => a= 12-b si inlocuim
3*(12-b) +7b= 56 36 -3b+7b= 56
4b= 56-36=20 4b=20 => b= 20:4=5
b=5 a= 12-5=7 a=7
verif (5+7):2 = 12:2=6 (media aritmetica)
(7*3+5*7): 10=(21+35): 10= 56 :10 = 5.6 (media ponderata)
