Question

Ma puteti ajuta cu urmatorul exercitiu?
Fie numerele a = 3 + 6+9+... + 60, 6 = 2 + 5+8+...+59, c = 1+4 + 7 + ... + 58.
Determinaţi numărul af = (a + 6 + c ) : ( 6 1 - 5 5 ) - ( a - 6 ) : 2 0 x ( a - c ) : 4

Answer 1

a=3(1+2+3+...+20)
a=3*20*21/2
a=3*10*21
a=63*10=630
b=2+3*1+2+3*2+2+....3*19+2
b=3+3*2+3*3+...3*19+2*19
b=3(1+2+3+...+19)+38
b=3*19*20/2+38
b=3*19*10+38
b-570+38=608
c=1+4+7+...+58
c=1+3*1+1+3*2+1+...+3*19+1
c=3*1+3*2+3*19+19
c=3(1+2+3+...+19)+19
c=3*19*20/2+19
c=3*19*10+19
c=570+19=589
f=(630+6+589):(61-55)-(630-6):20*(630-589):4
f=1225:6-624:20*341:4
f=1225/6-2659,8