Question

Intr-un cos avem mere.Numarul lor este mai mare decat 13 si mai mic decat 99.Daca numaram toate merele din cos 5 cate 5,ramane in cos 1 mar.
a)Cate mere  pot fi in cos?
b)Daca,in plus,numaram toate merele din cos 5 ctae 5,ramane in cos 1 mar.
Cate mere pot fi in cos de data aceasta?

Answer 1

a=nr.merelor
13>a.<99

nr merelor poate fi din 3 in 3,din 4 in 4 ,sau din 6 in 6
a)  din 3 in 3  - 15+2=17,20,23,26,29,32,35,38,41,44,47,50,53,56,59,62,65,68,71,74,77,80,83,86,89,91,94,97.
   din 4 in 4
16+2=18,22,26,30,34,38,44,48,52,56,60,64,68,72,76,80,84,88,92,96.
   din 6 in 6
 18+2=20,26,32,38,46,52,58,64,70,76,82,88,94
Cate mere pot fi in cos? cautam nr care le gasim lin toate 3 randurile
26,sau 38  mere pot  fi in cos
3+3+3+3+3+3+3+3+2=24    4+4+4+4+4+4+2= 26  6+6+6+6+2=26
3+3..........de 12 ori+2=38    4+4 de9 ori      +2=38  6+6+6+6+6+6+2=38
b)din 5 in 5+1
in cos pot fi  16,21,26,31,36,41,46,51,56,61,66,71,76,81,86,91,96.
26 de mere