Question

A school band consist of 45 boys and 50 girls. Of the total number of boys, 18 play the drums. What percent of the boys in the band play the drums?

Answer 1

that would be 8.1 if you divide

Answer 2

use the rule of  3 simple 

45 boys mean 100%
18 boys ------- x%
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 x = 18*100/45 = 40 

so this mean that 40% of the total number of boys play the drums 

hope helped