What will be the Difference in Ratio of Speed Altogether Between the Two Horses? If

Two horses A and B run at a speed of 3:2 ratio in the first lap; during the second lap the ratio differs by 4:7; during the third lap the ratio differs by 8:9. What is the difference in ratio of speed altogether between the two horses?

1. 2
2. 1
3. 3
4. 4