mon cau long co so ban nam yeu thich nhieu nhat.So luong 14 ban

mon bong ro co so hoc sinh u yeu thich nhieu hon hoc sinh nam va hon 2 ban

so vien gach lat phong do la:

30:0,25=120(vien)

so tien lat gach la:

110000.30=3 300 000(dong)

goi so hoc sinh di tham quan la x

theo de bai,ta co

(x-11):27;(x-11):36

suy ra,(x-11):BC(27,36)

ta co:27=3^3;36=6^2

BCNN(27,36)=3^3.6^2=324

BC(27,36)={0;324;648;972.....}

400<x<450 nen x-11=324

x=324+11=335

(-35).x=-210

x=(-210):(-35)

x=6

vay x=6

khoi luong trai dat gap khoi luong mat trang la:

6.10^21:75.10^18=8,1(lan)

[(195+5):8+195-400

=[(200:8+195]-400

=(25+195)-400

=-180

(-5).145.(-20)

=145.[(-5).(-20)]

=145.100

=14500

(-5).145.(-20)

=145.[(-5).(-20)]

=145.100

=14500

(-5).145.(-20)

=145.[(-5).(-20)]

=145.100

=14500