Question

M-am gandit la un numar.Il dublez apoi adun 15 si rezultatul il impart la 3.Obtin numarul 17.Care este numarul la care m-am gandit?

Answer 1

A x 2 + 15 : 3 = 17                                      a = 12 : 2

a x 2 + 5 = 17                                             a=6

2a + 5 + 17

2a = 17 - 5

2a=12

Answer 2

(y*2+15):3=17
y*2+15=17*3
y*2+15=51
y*2=51-15
y*2=36
y=36:2
y=18

verificare: (18*2+15):3=(36+15):3=51:3=17