The two equal-arm scales shown are balanced.
Of the following, has the same mass as
, 2019
Solutions — 2
Solution 1
The first scale shows that [[IMAGE0]] has the same mass as [[IMAGE1]] .
The second scale shows that [[IMAGE2]] has the same mass as [[IMAGE3]] .
Therefore, the sum of the masses of [[IMAGE4]] and [[IMAGE5]] is equal to the sum of the masses of [[IMAGE6]] and [[IMAGE7]] .
That is, the equal-arm scale shown below is balanced.
[[IMAGE8]]
The left and right sides of this scale each contain a [[IMAGE9]] , and the scale remains balanced if one [[IMAGE10]] is removed from each side of the scale (since they are equal in mass).
That is, the equal-arm scale shown below is balanced.
[[IMAGE11]]
Therefore of the answers given, [[IMAGE12]] has the same mass as [[IMAGE13]] .
Solution 2
On the spinner given, the prime numbers that are odd are and 7.
Since the spinner is divided into 8 equal sections, the probability that the arrow stops in a section containing a prime number that is odd is .
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