In a class of 42 students, the number of boys is 12 fewer than twice the number of girls. find the number of girls

Let the number of girls be x.

Given condition: Total number of student in a class is 42 students and the number of boys is 12 fewer than twice the number of girls.

As per the given condition" the number of boys is 12 fewer than twice the number of girls"

twice the number of girls means 2x

12 fewer than twice the number of girls which means 2x -12.

Therefore,

the number of boys = 2x-12                      

Total number of students in class = number of boys + number of girls

⇒    42 = 2x -12 +x

Combine like terms on RHS,

42 = 3x -12

Add 12 to both sides in above equation;

42+12 = 3x-12+12

Simplify:

54 = 3x

Divide by 3 to both sides we have;

Simplify:

18 =x or

x = 18

therefore, the number of girls be x = 18.

b) 1/3 * 1/5

step-by-step explanation:

each smallest part is 1/15 since the written one is 1/5 and it's divided by 3 equal parts. (1/5 )/3 = 1/15 = 1/3 * 1/5