math
posted by keyla .
PUC raised money for the recent disaster victims. they decided to allocate the money in this manner:
1/2 of the money raised goes to medical supplies
1/4 of what was left bought tents
2/3 of the remaining money went to water purification systems
the rest of the money was spent on shipping.
a. if $400 was spent on water purification systems, how much was allocated to each of these other categories:
medical
tents
shipping
b. what was the total amount collected.
please help me i have no clue as to what i am suppose to do

$X = Amt. raised.
X/2 = Amt spent for meds.
Bal = $X/2.
1/4 * X/2 = X/8 spent for tents.
Bal = X/2  X/8 = 4x/8  X/8 = 3X/8.
2/3 * 3X/8 = 6X/24 = X/4 Spent for water
purification.
Bal = 3X/8  X/4 = 3X/8  2X/8 = X/8.
X/8 Spent for shipping.
Bal = X/8  X/8 = $0.
a. X/4 = $400.
X = $1600 = Amt. raised.
X/2 = 1600/2 = $800 For Meds.
X/8 = 1600/8 = $200 ForTents.
X/8 = 1600/8 = $200 For Shipping.
b. X/4 = $400.
X = $1600 Raised. 
Thank you so much