a+b+c=100
a-n = 16; a-16 = n
b-n = 21; b-21 = n
c-n = 36; c-36 = n
a-16 = b-21 = c-36
Adunam 36 la fiecare
a-16+36 = b-21+36 = c-36+36
a+20 = b+15 = c
c = a+20
b = a+20-15 = a+5
Inlocuim in suma
a + a+5 + a+20 = 100
3a + 25 = 100
3a = 75
a = 25
b = 30
c = 45
n = 9
