10% of a number is 19. The number = □

190. number × 10% = 19, so the number = 19 ÷ 10% = 190. Or find 1% first: 19 ÷ 10 = 1.9, then times 100.

A club has 1000 members. 40% of them went on a trip, and 25% of those on the trip were women. □ went on the trip, □ of them women. Fill in each blank

400, 100. A step at a time, each on its own base: 1000 × 40% = 400, and 400 × 25% = 100.

Take 80% of a number, then 25% of that. What percentage of the number is it? A. 20% B. 2000% C. 105% D. 200% Choose the right answer

A. 20%. Let the number be 100: 80% of it is 80, and 25% of that is 80 × 25% = 20, so 20% of the number.

Percentages (I) · Ages 12–13

A part as a percentage of the whole

Percentage = part ÷ whole × 100%; whole = part ÷ percentage.

How to do it

Method

Percentage = part ÷ whole × 100%; whole = part ÷ percentage

14 ÷ 40 × 100% = 35%

Another way

Find 1% first

27 ÷ 15 = 1.8, 1.8 × 100 = 180

In full

A part as a percentage of the whole = part ÷ whole × 100%. 14 of 40 people wear glasses: 14 ÷ 40 × 100% = 35%. The other way, the whole from a part: 15% of a number is 27, so the number = 27 ÷ 15% = 27 ÷ 0.15 = 180. Or find 1% first: 27 ÷ 15 = 1.8 is 1%, so 100% is 1.8 × 100 = 180 — the same. A percentage of a percentage goes a step at a time: 40% of 200 people is 80, and 25% of them is 80 × 25% = 20; or all at once, 200 × 40% × 25% = 20 — never 200 × (40% + 25%). A mixture's concentration is a part of the whole too: 30 g of sugar in 120 g of sugar water is 30 ÷ 120 × 100% = 25%; add water and the sugar stays the same while the whole grows.

Worked examples

Have a go first, then open each one for the answer and the working.

Example 1
10% of a number is 19. The number =
Show the answer and working
Answer: 190
number × 10% = 19, so the number = 19 ÷ 10% = 190. Or find 1% first: 19 ÷ 10 = 1.9, then times 100.
Example 2
A club has 1000 members. 40% of them went on a trip, and 25% of those on the trip were women. went on the trip, of them women.
Fill in each blank
Show the answer and working
Answer: 400, 100
A step at a time, each on its own base: 1000 × 40% = 400, and 400 × 25% = 100.
Example 3
Take 80% of a number, then 25% of that. What percentage of the number is it?
- A. 20%
- B. 2000%
- C. 105%
- D. 200%
Choose the right answer
Show the answer and working
Answer: A. 20%
Let the number be 100: 80% of it is 80, and 25% of that is 80 × 25% = 20, so 20% of the number.

Practice questions to try

Try these 5; the answers are at the end. For a whole worksheet, see VIP worksheets below.

1.What is 20% of 240?
- A. 480
- B. 192
- C. 288
- D. 48
Choose the right answer
Answer:
2.60 of 200 people wear glasses. Those wearing glasses are % of them all
Answer:
3.Take 60% of a number, then 75% of that. What percentage of the number is it?
- A. 45%
- B. 135%
- C. 4500%
- D. 450%
Choose the right answer
Answer:
4.A club has 500 members. 20% of them went on a trip, and 25% of those on the trip were women. went on the trip, of them women.
Fill in each blank
Answer:
5.20% of a number is 58. The number =
Answer:

All the answers

1. D. 48
2. 30
3. A. 45%
4. 100, 25
5. 290

Free worksheet: A part as a percentage of the wholeWorking out, multiple choice and word problems, with answers and working, to print or save as a PDF

VIP practice notes and papers

Aimed at tests and exams: questions on this topic, new every time, to print or save as a PDF.

Practice notes: The key point, worked examples step by step, then questions of the same kind to follow, hints fading
Practice paper: Set out in parts like a school paper, marked, with answers and full working

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