Use a system of equations to model the situation and then solve by any method.
An orchestra consists of string instruments and wind instruments in a ratio of 9 to 4. There are 91 string and wind instruments in the orchestra. How many string instruments are there? How many wind instruments?
63 string instruments 28 wind instruments
65 string instruments 26 wind instruments
60 string instruments 31 wind instruments
72 string instruments 19 wind instruments
Ratio of 9:4 means that there are 13 (9 + 4) parts
Since there are a total of 91 instruments, then number of strings =
Number of winds: , or 91 -
OR
Let the multiplicative factor be x
Then we can say that: 9x + 4x = 91
Solve for x
Multiply x by 9 to get number of strings
Multiply x by 4, or subtract number of strings from 91 to get number of winds.