Let the number b be the equation of X series (x+90)*4/5=5/7 *x +90. In this equation, 5/7 *x is the beginning of the number A, and x is the beginning of the number B. After adding 90, two subsequent numbers are obtained. Their relationship is 4/5, which should be the number after the change of number B (x+90

X=2 10 B is 2 10, and A is 2 10*(5/7)= 150.

Attach the process of solving the equation:

4/5*x+72=5/7*x +90

(4/5-5/7)*x= 18

3/28 *x= 18

x=2 10