Solve for 17 Exam Questions: Finding Distribution Across 3 Parts

Question

A theory exam consists of 17 questions and is divided into three parts.

The second part has 3 fewer questions than the first part and the last part has half the number of questions as the first part.

How many questions are there in each part?

Video Solution

Solution Steps

00:00 How many questions are in each part?
00:03 Let's mark the number of questions in part 1 using the unknown X
00:06 Let's express the number of questions in other parts using X
00:10 Let's build an appropriate equation according to the given data
00:14 The sum of questions equals 17
00:18 Let's group terms
00:27 Let's arrange the equation so that one side has only the unknown X
00:31 Let's isolate X
00:39 Let's convert from number and fraction to fraction
00:44 Let's write division as multiplication by reciprocal
00:47 Let's divide 20 by 5
00:50 This is the solution for X
00:53 Let's substitute this solution to find the number of questions in each part

Step-by-Step Solution

To solve the problem, follow these steps:

  • Define variable x x as the number of questions in the first part.
  • Express the number of questions in the second and last parts in terms of x x , which are x3 x-3 and x2\frac{x}{2} respectively.
  • Set up the equation for the total number of questions: x+(x3)+x2=17 x + (x - 3) + \frac{x}{2} = 17 .

Now, let's solve the equation:
Combine like terms:
x+x3+x2=17 x + x - 3 + \frac{x}{2} = 17
This simplifies to:
2x+x23=17 2x + \frac{x}{2} - 3 = 17 .

Clear the fraction by multiplying the entire equation by 2:
2(2x)+2(x2)2(3)=2(17) 2(2x) + 2\left(\frac{x}{2}\right) - 2(3) = 2(17) ,
which simplifies to:
4x+x6=34 4x + x - 6 = 34 .

Combine the terms:
5x6=34 5x - 6 = 34 .
Add 6 to both sides:
5x=40 5x = 40 .
Divide by 5 to solve for x x :
x=8 x = 8 .

The number of questions in the first part is 8.

To find the number of questions in the second part, calculate x3 x - 3 :
83=5 8 - 3 = 5 .

For the last part, calculate x2\frac{x}{2}:
82=4\frac{8}{2} = 4 .

In conclusion, there are 8 questions in the first part, 5 questions in the second part, and 4 questions in the last part.

Therefore, the solution to the problem is 8,5,4 8, 5, 4 .

Answer

8,5,4 8,5,4