| Quick
Answer:Their weights are:
| |
= |
2
pounds |
| |
= |
3
pounds |
| |
= |
4
pounds |
|
|
Complete
Solution:
There are many ways to solve this problem.
| |
Add the weights on all 3 scales, so,
|
| 
|
+ |
|
+ |
|
= |
18 pounds |
| |
|
+ |
|
+ |
|
= |
9 pounds |
But from Scale #2 we know that:
|
+ = 7
pounds |
| |
= 2
pounds |
Since the little fish
weighs 2 pounds,
and we know from Scale #3 that:
|
+ = 5
pounds |
| |
= 3
pounds |
| |
+ =
6 pounds |
| |
= 4 pounds |
| |
| |
If you put the fish with weights 6 and 7 together
on the scales, then
|
|
|
+ |
|
+ |
|
= |
13 pounds |
But we know from Scale #3,
|
+ = 5
pounds |
| |
+ =
8 pounds |
| |
= 4 pounds |
| |
Strategy #3
Consider the weights in the two balloons showing 6 and
7. The weights differ by one pound and the big
fish is on both scales, so the medium
fish weighs 1 pound more than the little
fish. The third scale shows that the combined
weights of the little fish
and medium fish is
5 pounds. Since the medium fish
weighs 1 pound more than the little
fish, the little fish
must weigh 2 pounds and the medium
fish 3 pounds. |
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