Zwelibanzi and Jessica are friends. Zwelibanzi takes Jessica’s civil technology test paper and will not tell her what her mark is. He knows Jessica dislikes word problems so he decides to tease her. Zwelibanzi says: : I have 12 marks more than you do and the sum of both our marks are equal to 148. What are our marks?

80 and 68

Step-by-step explanation:

Jessica's marks = x

Zwelibanzi's marks = y

We get following equations as per given:

Sum up the two equations to substitute x:

And finding the value of x:

Marks are: 80 and 68

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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step-by-step explanation:

answer: 486in^2

step-by-step explanation: