SOLUTION: weight of a tank full with water is 27.5kg.Its weight is 12.2kg when the tank is 1/4 full.Find weight of empty tank

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: weight of a tank full with water is 27.5kg.Its weight is 12.2kg when the tank is 1/4 full.Find weight of empty tank      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 769883: weight of a tank full with water is 27.5kg.Its weight is 12.2kg when the tank is 1/4 full.Find weight of empty tank
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Let m = mass of the tank by itself (when empty).
Let w = mass of water in FULL tank.

Full tank is m%2Bw=27.5 kg.
Quarter-full tank is m%2Bw%2F4=12.2 kg.

Those are two equations using unknown variables m and w. Various ways possible to solve the system.

m%2Bw%2F4=12.2+,
4%28m%2Bw%2F4%29=4%2812.2%29
4m%2Bw=48.8
%284m%2Bw%29-%28m%2Bw%29=48.8-27.5 which is just subtracting the Full equation from the Quarter-full equation.
3m=21.3
highlight%28m=7.1%29 kg., the empty tank.



-------
You can continue for finding w. Either original equation can be used.
m%2Bw=27.5
w=27.5-m
since we found m now,
w=27.5-7.1
highlight%28w=20.4%29 kg. water when full.