Solution: Let the original price of A be 7X yuan and the original price of B be 3X yuan.

(7X+70):(3X+70)=7:4

28X+280=2 1X+490

7X=2 10

X=30

The original price of A is: 7× 30 = 2 10 (yuan).

B Original price: 3× 30 = 90 yuan.