We set up a proportion: 84/?= 56/100
Cross multiply: 56*?= 84*100
⇒ ?= 84*100/56= 150
56% of 150 is 84.
Using the combination formula, it is found that Julia can take 15 combinations.
<h3>What is the combination formula?</h3>
is the number of different combinations of x objects from a set of n elements, given by:

For this problem, 4 students are taken from a set of 6, hence the number of combinations is given as follows:

More can be learned about the combination formula at brainly.com/question/25821700
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Since x co-ordinates are constant, answer has to be difference in y co ordinates therefore the answer is 4
I’m not sure but I think 4 classes have between 27 and 31 students