Question

[do thanh nhan]

trong hoc ki 1 so hoc sinh kha cua khoi 6 bang 2\3 so hoc sinh con lai sang hoc ki 2 co them 4 em xep loai kha nua nen so hoc sinh xep loai kha bang 11\14 so hoc sinh con lai tim so hoc sinh khoi 6 biet so hoc sinh trong ca hai hoc ki khong thay doi

Answer 1

[ST]

A=3+3³+...+3²⁹+3³¹

3³A = 3³+3⁵+...+3³¹+3³³

27A - A = (3³+3⁵+...+3³¹+3³³) - (3+3³+...+3²⁹+3³¹)

26A = 3³³ - 3

A = \(\frac{3^{33}-3}{26}\)

Answer 2

[Vuong Song Toan]

3A=3^2+3^3+3^4+.............+3^32

3A-A=3^32-3

A=3^32-3/2