Stephanie wants to make 22.5 qt. of a 20% alcohol solution by mixing together a 6%

alcohol solution and a 36% alcohol solution.

How much of each solution must she use?

y = 10.5qt

x = 12 qt

Step-by-step explanation:

0.6x+ 0.36y = 22.5 * 0.2

0.06x + 0.36y = 4.5

x + y = 22.5

x = 22.5 - y

0.06(22.5 - y) + 0.36y = 4.5

1.35 - 0.06y + 0.36y = 4.5

0.3y = 4.5 - 1.35

0.3y = 3.15

y = 3.15 / 0.3

y = 10.5 qt

x = 22.5 - y

x = 22.5 - 10.5

x = 12 qt

$30.32

step-by-step explanation:

65.00*.12=2.80

65.00-2.80=57.20

57.20*1.06=60.632

60.632/2=30.316

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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