In a 145-member choir of only altos and sopranos, there are 37 more (September 2023 - G01)

Correct answer: C. 91:54.
Let's denote the number of sopranos as S and the number of altos as A. We are given that there are 145 members in total, so we can set up the equation:
S + A = 145
We're also given that there are 37 more altos than sopranos, so:
A = S + 37
Now, we can substitute the value of A from the second equation into the first equation:
S + (S + 37) = 145

Solving this equation:
2S + 37 = 145
2S = 108
S = 54
Now that we have found the number of sopranos, we can find the number of altos:
A = S + 37 = 54 + 37 = 91

So, there are 91 altos and 54 sopranos in the choir.
Now, to find the ratio of altos to sopranos, we use the ratio A:S:
Ratio = A/S = 91/54

So, the correct answer is option C:91:54.