Question

un camion a transportat la prima cursa 5 supra 21 dintr-o cantitate de marfa iar la cursa urmatoare 2 supra 15 mai multa marfa Aflati ce fractie din cantitate de marfa atransportat camionul in cele 2 curse la un loc?

Answer 1

5/21 + 2/15 = 25/105 + 14/105 = 39/105 A TRANSPORTAT A 2-A ZI
21 = 3 * 7
15 = 3 * 5 
C.M.M.N.C. = 3 * 5 * 7 = 105
5/21 + 39/105 = 25/105 + 39/105 = 64/105 A TRANSPORTAT IN CELE 2 ZILE

Answer 2

Aflam cata marfa a transportat a doua zi
$\frac{5}{21}$ + $\frac{2}{15}$ = $\frac{5*5}{105}$ + $\frac{2*7}{105}$ =$\frac{39}{105}$ kg
Aflam cata marfa a transportat in cele 2 curse,total.

$\frac{5}{21}$ +$\frac{39}{105}$ =
$\frac{5*5}{105}$ +$\frac{39}{105}$ =$\frac{64}{105}$ kg