1. Part of a Whole
Finding a specific amount from a total
Amount = Total × Fraction
Multiply the total quantity by the fraction given to find the specific part.
Example
A library has 120 books, and $$\frac{3}{5}$$ of them are fiction. How many fiction books are there?
Show solution
Step 1: Identify total = 120 and fraction = $$\frac{3}{5}$$.
Step 2: Multiply Total × Fraction:
- Amount $$= 120 \times (\frac{3}{5}) = \frac{(120 \times 3)}{5} = \frac{360}{5} = 72$$.
Result: 72 fiction books.
Practice problems
-
Problem 1
A class has 30 students, and $$\frac{2}{3}$$ of them are girls. How many girls are in the class?
Show solution
Answer: 20 girls
Step 1: Total students = 30, fraction = $$\frac{2}{3}$$.
Step 2: Calculate Girls $$= 30 \times (\frac{2}{3}) = \frac{(30 \times 2)}{3} = \frac{60}{3} = 20$$.
=> Correct Answer: A (20 girls).
-
Problem 2
A bakery made 240 cookies. If $$\frac{5}{8}$$ of the cookies were chocolate chip, how many chocolate chip cookies were made?
Show solution
Answer: 150 cookies
Step 1: Total cookies = 240, fraction = $$\frac{5}{8}$$.
Step 2: Calculate $$= 240 \times (\frac{5}{8}) = (\frac{240}{8}) \times 5 = 30 \times 5 = 150$$.
=> Correct Answer: A (150 cookies).
-
Problem 3
In a company of 450 employees, $$\frac{4}{9}$$ work in marketing and $$\frac{2}{5}$$ of the remainder work in sales. How many work in sales?
Show solution
Answer: 100 employees
Step 1: Marketing employees = $$450 \times (\frac{4}{9}) = 200$$.
Step 2: Remainder employees $$= 450 - 200 = 250$$.
Step 3: Sales employees $$= 250 \times (\frac{2}{5}) = 100$$.
=> Correct Answer: A (100 employees).