SOLUTION: A box contains steel balls. There are 28 balls,some weighing 3/4 kg and the others 7/8 kg each. The weight of all the balls is 22 1/2 kg. How many balls of each size are in the box

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Question 1082439: A box contains steel balls. There are 28 balls,some weighing 3/4 kg and the others 7/8 kg each. The weight of all the balls is 22 1/2 kg. How many balls of each size are in the box?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the number of 3/4 kg balls, B the 7/8 kg balls.
1.A%2BB=28
.
.
%283%2F4%29A%2B%287%2F8%29B=22%261%2F2
Multiply both sides by 8.
2.6A%2B7B=180
Multiply eq. 1 by 6 and subtract from eq. 2,
6A%2B7B-6A-6B=180-28%2A6
B=12
Now use either equation to solve for A.