Sample question for ACT math preparation

Question

Brandy has a collection of comic books. If she adds 15 to the number of comic books in her collection and multiplies the sum by 3, the result is 65 less than 4 times the number of comic books in her collection. How many comic books are in her collection?

Answer 1

Let x represent the number of comics

 

3(x+15)=4x-65

3x+45=4x-65

 

3x+45=4x-65

-3x+65=-3x+65

==========

      110=x

 

the number of comics in collection is 110

 

to check

110+15=125*3=375

4*110=440-65=375 ..check

 

 

Answer 2

Let's take this problem step-by-step:

1. Let's represent the number of comic books in Brandy's collection as x.

2. According to the problem, if Brandy adds 15 to the number of her comic books and then multiplies the sum by 3, the result is 65 less than 4 times the number of her comic books. We can translate this into an equation:

3(x + 15) = 4x - 65

3. Now, we can simplify and solve this equation. First, distribute the 3 on the left side:

3x + 45 = 4x - 65

4. Next, get all the x terms on one side and the numbers on the other. We can do this by subtracting 3x from both sides and adding 65 to both sides:

45 + 65 = 4x - 3x

110 = x

So, Brandy has 110 comic books in her collection.