Question

suma a 5nr. consecutive impare este 75. afla nr

Answer 1

fie x+1,x+3,x+5,x+7,x+9 nr
avem ecuatia:x+1+x+3+x+5+x+7+x+9=75
5x+25=75
5x=75-25
5x=50
x=50:5
x=10
raspuns:11,13,15,17,19
verificare:11+13+15+17+19=24+15+17+19=39+36=75

Answer 2

l___l
l___l_2_l
l___l_2_l_2_l
l___l_2_l_2_l_2_l
l___l_2_l_2_l_2_l_2_l
 
2 x 10=20
75-20=55 (suma segmentelor egale)
55:5=11 (un segment) = primul numar
11+2=13 al doilea numar
13+2=15 al treilea numar
15+2=17 al patrulea numar
17+2=19 al cincilea numar