Ireally need these two it’s okay if you can do one.

20. 20 workers

21. 15 hits

Step-by-step explanation:

20. To complete the job in 9/15 of the time will require 15/9 times as many workers, since the relation is inversely proportional.

15/9·12 = 20

20 workers will be required.

21. You want x such that ...

(12+x)/(60+x) = 0.360

12 +x = 0.360(60 +x) . . . . multiply by the denominator

0.64x = 21.6 -12 . . . . . . . . subtract 12+0.36x

9.6/0.64 = x = 15 . . . . . . . divide by the coefficient of x

15 consecutive hits are required to raise the batting average.

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This can also be worked by rewriting the rational expression.

1 - 48/(60+x) = 0.360 . . . . rewrite to quotient and remainder

1 - 0.360 = 48/(60 +x) . . . add 48/(60+x) - 0.360

60 +x = 48/0.64 = 75 . . . . multiply by (60+x)/0.64

x = 15 . . . . . . . . . . . . . . . . . subtract 60

191 students play sports and ninety-seven 10th graders were surveyed.

step-by-step explanation: