SOLUTION: Hi box a is 3.45 kg heavier than box b.when 1.2 kg in box a was removed, box a became 4 times as heavy as box b.what was the mass of box a in the beginning. help!

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Question 941677: Hi
box a is 3.45 kg heavier than box b.when 1.2 kg in box a was removed, box a became 4 times as
heavy as box b.what was the mass of box a in the beginning.
help!

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = mass in kg of box a at beginning
Let +b+ = mass in kg of box b at beginning
--------------------
given:
(1) +a+=+b+%2B+3.45+
(2) +a+-+1.2+=+4b+
---------------------
(1) +a+-+b+=+3.45+
(2) +a+-+4b+=+1.2+
-------------------
Subtract (2) from (1)
(1) +a+-+b+=+3.45+
(2) +-a+%2B+4b+=+-1.2+
----------------------
+3b+=+2.25+
+b+=+.75+
and
(2) +a+-+1.2+=+4%2A.75+
(2) +a+=+1.2+%2B+3+
(2) +a+=+4.2+
Box a was 4.2 kg
----------------
check:
(1) +a+-+b+=+3.45+
(1) +4.2+-+.75+=+3.45+
(1) +3.45+=+3.45+