4.In Amy’s English class, 30% of the students play an instrument. She does not know how many in the whole school play an instrument, but there are 500 students in the school.
A.Solve the proportion 30/100=n/500 to estimate the total number of students in the school who play an instrument.
30/100=n/500
Cross multiply.
100n = 15,000
Solve for n
n = 150
To solve the proportion, we will use cross-multiplication.
The proportion is: 30/100 = n/500
Cross-multiplying, we get: (30)(500) = (100)(n)
15000 = 100n
To isolate 'n', we can divide both sides of the equation by 100:
15000/100 = 100n/100
150 = n
Therefore, an estimated total of 150 students in the school play an instrument.