Z-scores are expressed in terms of standard deviations from their means. <span>The standard score is simply the score, minus the mean score, divided by the standard deviation. It is calculated as follows:
z = X- mean / standard deviation
z = 2.7 - 2.4 / 1.5
z = 0.2</span>
The answer is: " 2 :5 " ; or, write as: " 2/5 " .
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The ratio of 'girls' to 'all students' is: "2: 5 " ; or, write as: " 2/5 ".
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Explanation:
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Given: The ratio of boys to girls is: " 3:2 " .
Problem: Find the ratio of "girls" to "all students:
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Note: This ratio of "boys to girls", which is " 3 : 2 " ;
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→ can be expressed as " 3x: 2x" ;
in which the total number of students is: " 3x + 2x " = 5x " .
→ The total number of students is represented as: " 5x " .
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→ The ratio of "girls to boys" is: "2x : 3x" .
→ {that is; the "inverse" of the ratio of "boys to girls"} ;
→ {that is; the "inverse" of " 3x: 2x" } ; → which is: " 2x : 3x " .
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The ratio of "girls" to "all students" is: "2x : 5x " ; or " 2x/5x " ;
→ Both "x" values cancel ; {since: " x/x = 1 "} ;
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→ and we have the answer: " 2 :5 " ; or, write as: " 2/5 " .
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The ratio of 'girls' to 'all students' is: " 2 :5 " ; or, write as: " 2/5 ".
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Given the table showing the distance Randy drove on one day of her vacation as follows:
![\begin{tabular} {|c|c|c|c|c|c|} Time (h)&1&2&3&4&5\\[1ex] Distance (mi)&55&110&165&220&275 \end{tabular}](https://tex.z-dn.net/?f=%5Cbegin%7Btabular%7D%0A%7B%7Cc%7Cc%7Cc%7Cc%7Cc%7Cc%7C%7D%0ATime%20%28h%29%261%262%263%264%265%5C%5C%5B1ex%5D%0ADistance%20%28mi%29%2655%26110%26165%26220%26275%0A%5Cend%7Btabular%7D)
The rate at which she travels is given by

If Randy has driven for one more hour at the same rate, the number of hours she must have droven is 6 hrs and the total distance is given by
distance = 55 x 6 = 330 miles.
ANSWER: x will equal 3 I hope this helps