Question

There are b boys in the class. This is three more than four times the number of girls. How many girls are in the class?

Answer 1

let boys = b
girls = g
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b = 3+4g
b-3= 4g
b-3/4 =g
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no.of girls = b/4-3/4

Answer 2

let x represent the unknown number that you are asked to find:  Let x be the number of girls.

(Although b is not known -- it is an arbitrary constant -- it is not what you are asked to find.)

The problem states that "This" -- b -- is three more than four times x:

 4x + 3 = b.  

 Therefore,

 4x = b − 3  

 

x = b − 3

  4 .

The solution here is not a number, because it will depend on the value of b.  This is a type of "literal" equation, which is very common in algebra.

hope it helps u dear