The numerator of the given fraction is 4 less than the denominator. If 5 is added to both numerator and denominator, the resulting fraction is equivalent to 5/7 . What is the original fraction? hlp!!!

5/9

Step-by-step explanation:

Let the denominator be k and thus numerator be 4 less than k or k - 4.

Fraction = (k - 4)/k

If 5 is added to both:

=> (k-4 + 5)/(k + 5) = 5/7

=> 7(k + 1) = 5(k + 5)

=> 7k + 7 = 5k + 25

=> 2k = 18

=> k = 9

Thus,

Fraction is (k-4)/k = (9-4)/9 = 5/9

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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