Answer: No
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Work Shown:
(5 altos)/(4 sopranos) = (15 altos)/(13 sopranos)
5/4 = 15/13
13*5 = 4*15 .... cross multiply
65 = 60
The last equation is false, so the first equation is false
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Alternative ratio
(5 altos)/(15 altos) = (4 sopranos)/(13 sopranos)
5/15 = 4/13
5*13 = 15*4
65 = 60
We end up with the same false equation
The given values are not in the same proportion.
The ratios are not equivalent.
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Yet another way to look at it
Note the jump from 5 altos to 15 altos is "times 3"
So if we started with 4 sopranos, then we must have 4*3 = 12 sopranos as our next count.
If the second line changed "13 sopranos" to "12 sopranos", then we would have equivalent ratios.
