Toan hoc ve khu

Cac dang toan ve khu
1.Bac Ba va bac Bac Tu di cho . Bac Ba di mua 2kg thit va mot kg ca het 10000dong .Bac Tu mua 3kg thit va 2 kg ca het 16400 dong .tim gia tien 1kg va 1 kg ca.
Bai lam
Ta co : 2 kg thit + 1 kg ca = 10000 dong [A]
3 kg thit +2 kg ca = 16400 dong [B]
Gap cac gia tri cua A len 2 lan , giu nguyen cac gia tri cua B .
Ta co : 4 kg thit + 2 kg ca = 20000 dong [C]
3 kg thit + 2 kg ca = 16400 dong [ D ]
1kg thit co so kg la : 20000 – 16400 = 3600 (dong)
2 kg thit co so kg la : 3600 x 2 = 7200 (dong)
1kg ca co so kg la :10000 – 7200 = 2800 (dong)
Dap so :thit : 7200 dong , ca : 2800 dong
2.3 ban Nam , Ha , Minh mua nhan vo . Biet Ha va Nam mua 27 cai, Nam va Minh mua 30cai, Minh va Ha mua 33 cai .Hoi moi ban mua bao nhieu cai nhan vo.
Bai lam
Ta co : Nam + Ha = 27 cai
Nam + Minh = 30 cai
Minh +Ha = 33 cai
Ca 3 ban co so nhan vo la :( 27 + 30 + 33 ) : 2 =45 [cai]
Minh co so nhan vo la : 45 – 27 = 18 [ cai]
Nam co so nhan vo la : 30 – 18 = 12 [cai]
Ha co so nhan vo la : 45-( 12 = 18) = 15 (cai)
Dap so Nam: 12 cai
Minh : 18 cai
Ha : 15 cai
3. Mua 5but chi mau va 3 but chi den gia 5100 dong .Biet gia 5 but chi mau dat hon 2 but chi den 1600 dong .Tinh gia tien 1 but chi moi loai.

Cac bai toan lien quan den tinh nguoc tu cuoi len
1.Tim 1 so , biet rang lay so do nhan voi 3 duoc bao nhieu cong voi 6 roi cuoi cung chia 3 thi duoc ket qua = 36
Bai lam
Goi so can tim la a : ta co
(a x 3 + 6 ) : 3 = 36
a x 3 + 6 = 36 x 3
a x 3 + 6 = 108
a x 3 = 108 – 6
a x 3 = 102
a= 102:3
a= 34
Vay so can tim la 34.