4 blue, 3 red
twice as many black pens as blue pens.....black pens = 2(4) = 8
so there are : (4 + 3 + 8) = 15 total pens
fraction of blue pens to total pens = 4/15
Since we know that 1/4 is equal to 25%, or 0.25 in decimal form, we are able to work with 0.75 in the expression.
We are told to use j as the original price of the jeans, so we can set up the expression:

to represent the cost of the jeans with the discount.
Then to simplify, we simply take out j as a common factor, and solve what's in the parentheses:

or 
Using this equation, we can solve for the b part of the question. If the pair of jeans originally costs $60, plug in 60 to where j is in the expression:


Therefore, the cost of the jeans after the discount is C) $45.
Combining those like terms would end as 3n.
Explanation: The end of a subtraction equation is basically just the negative number, except you add it to the other part.
For example, 2n is really -2n, and you just add -2n to 5n (which is positive,) and you get 3n.