Ex. 13
a)(12+18)÷2=15
b)(204+305)÷2=254,5
c)(7+8,4)÷2=7,7
d)(9+14,32)÷2=11,66
e)(10,5+47,34)÷2=28,92
f)(10,12+30,2)÷2=20,16
Ex. 14
a)[tex] \frac{(x+8,4)}{2}= \frac{14.75}{2} [/tex]
x+8,4=29,5
x=21.1
b)(a+b+....+z):100 = 47,58
(a+b+....+z) = 47,58 x 100
(a+b+....+z) = 4758
*(a+b+....+z) contine 100 de termeni in diferite notatii
c)(21+14.4+34.6+x ) : 4 =29
media aritmetica este egala cu a+b+c: impartit la cate nr sunt =>
(70+x ): 4=29
=>mezii si extremii
70+x=29*4
x=116-70
x=46
