Algebra Riddle; Find The Weight?

[dabomb_isback]

Together, Cat A) and Cat B) weigh 18kg; Cat B) is one and a half the weight of Cat A) how much does each cat weigh?

 

[rey]

Together, Cat A) and Cat B) weigh 18kg: A + B = 18
Cat B) is one and a half the weight of Cat A): B = 1.5A
substitute b (in the 2nd equation) into the 1st equation:
A + B = 18
A + 1.5A = 18
2.5A = 18
divide both sides by 2.5
A = 7.2 kg

plug A into 2nd equation:
B = 1.5 * 7.2
B = 10.8 kg