Răspuns :
m + p = 15
pr = 40 - 15 = 25
pr + m = 14
25 + m = 14
m = 25 - 14 = 11
m + p = 15
p = 15 - 11 = 4
25 + 11 + 4 = 40
pr = 40 - 15 = 25
pr + m = 14
25 + m = 14
m = 25 - 14 = 11
m + p = 15
p = 15 - 11 = 4
25 + 11 + 4 = 40