To solve this problem, we need to determine the value of x, which represents the number of cups brought by each boy in the class.
Let's break down the information given:
Number of students in the class: 30
Number of boys in the class: 10
Number of girls in the class: 2 * 10 = 20
Total number of cups brought by the students in the class: 90
Number of cups brought by each boy: x
Number of cups brought by each girl: 2
We can set up the equation as follows:
Number of boys * Number of cups brought by each boy + Number of girls * Number of cups brought by each girl = Total number of cups brought by the students in the class
10x + 20 * 2 = 90
Let's simplify and solve for x:
10x + 40 = 90
To isolate x, we subtract 40 from both sides of the equation:
10x + 40 - 40 = 90 - 40
10x = 50
To solve for x, we divide both sides of the equation by 10:
x = 50 / 10
x = 5
The value of x is 5.
#### 5
The answer is: 5
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
There are 30 students in Ms. Leech's class. Twice as many girls as boys are in the class. There are 10 boys in the class and each boy today brought x cups for science activity class as Ms. Leech had instructed. If the total number of cups brought by the students in the class is 90, Each girl brought 2 cups. What is the value of unknown variable x?

### Answer:
