Question 204654
Ann's age = A
Bill's age = B


A = 7/10 * B
In 4 years:
A + 4 = 8/11 * (B + 4)
7/10 * B + 4 = 8/11 * B + 32/11
7/10 * B - 8/11 * B = 32/11 - 4
(77/110 - 80/110) * B = 32/11 - 44/11
(-3/110) * B = -12/11
B = -12/11 * -110/3
B = 40
A = 7/10 * 40 = 28


so,Bill is 40 years old now