Can anyone give an explanation and solution for henry park 2011 prelim maths.

Q17:there were 1000 students at the parade ground and indoor sports hall. 40% of the 600 students at the parade ground were girls. 60% of the students at the indoor sports hall were girls. After some of the students in both venues moved from one venue to the other, 30% of the students in the parade ground and 70% of the students at the indoor sports hall were girls. How many students were there in the indoor sports hall after the movement had taken place? Ans: 450
Q18: A large warehouse had a total of 2180 black, red and white t-shirts for sale. the ratio of black t shirt to red t shirts was 3:1. after 2/5 of the black t shirts and 1/3 of the white t shirts and none of the red t shirts were sold, there were 1504 t shirts left. how many red t shirts were there at first? ans: 380

Hi,


Can anyone give a clear explanation on how to solve the problem in RGS Prelim Maths 2011 Paper 2 Question 18?
The question is: Beaker A and Beaker B contain some water. If 46.5 ml of water is drained out from Beaker A, the volume of the water in beaker A will be 60% that of the water in Beaker B. If 32.5 ml of water is drained out from Beaker B will be 85% that of the water in Beaker A. What is the total volume of water in Beaker A and Beaker B?
Ans:290.5 ml