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Word problemsArithmeticMiddle schoolabout 0:41

A recipe needs 3 cups of flour for 12 cookies. How many cups for 30 cookies?: animated lesson

A narrated, step-by-step word problems video lesson with captions. Final answer: 7.5 cups.

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.3 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Worked example
A recipe needs 3 cups of flour for 12 cookies. How many cups for 30 cookies?
2. Step by step
1. Set up the proportion
2. Cross-multiply
3. The answer
$\text{7.5 cups}$
7.5 cups
4. Check
- 7.5 / 30 = 0.25 = 3/12 ✓

Transcript

The problem. Here is the problem: A recipe needs 3 cups of flour for 12 cookies. How many cups for 30 cookies? Proportion: 3 cups for 12 cookies; find the amount for 30 cookies.

Step by step. Set up the proportion. 3 over 12 equals x / 30. Cross-multiply. x equals 3 times 30 over 12 equals 7.5.

The answer. So the answer is 7.5 cups. Proportion: 3 cups for 12 cookies; find the amount for 30 cookies.

Check. 7.5 over 30 equals 0.25 equals 3 over 12, which checks out.

About word problems

Turn everyday situations about prices, speed, ages and interest into equations and solve them.

A recipe needs 3 cups of flour for 12 cookies. How many…