Question

4+7+10+13+...+334=?

Answer 1

Răspuns

18759

Explicație pas cu pas:

4+7+10+13+......+334 = (4+334)·111:2 = 338·111:2 = 169·111 = 18759

(334-4):3+1 = 111 termeni

Answer 2

4 + 7 + 10 + 13 + ................. + 334 =

Se observa ca numerele cresc din 3 in 3..

4 = 3 × 1 + 1

7 = 3 × 2 + 1

10 = 3 × 3 + 1

................................................

..................................................

334 = 3 × 111 + 1

Dam factor comun pe 3 .................

$S = 3 * ( 1 + 2 + 3 + .......... + 111 ) + 111$

$= 3 * [ 111 * ( 111 + 1 ) : 2 ] + 111$

$= 3 * ( 111 * 112 : 2 ) + 111$

$= 3 * ( 12432 : 2 ) + 111$

$= 3 * 6216 + 111$

$= 18648 + 111$

$= 18759$