Answer:
Option E
Explanation:
I) X5:Y4=1:2
⇔X5×4Y =12
⇔XY
=(12×54)
=58
⇔X:Y=5:8
II) 20Y=XY
Let X's age be 5x years. Then Y's age is 8x years.
∴ 20×8x
=5x×8x ⇔40x=160
⇔x=4.
∴ X=20 and Y=32.
Thus, I and II together give the answer. So, correct answer is (E)