30g of sugar is used to make 4 cakes. How much sugar is used to make 7 cakes
2 answers:
Answer:
52.5g of sugar is used to make 7 cakes.
Step-by-step explanation:
I love this topic. <3 This is called Scale factors.
If 30 per 4, then how many per 7? is the question. I can't explain this very well on the computer, but maybe I can with picture.
To get from 4 to 7, multiply by 7/4. I forgot what rule/property this is, but it says that if x*z=y, z = y/x. It is helpful!
So now, the scale of the ratio 4:7 is 7/4. This is the same scale of 30:?. Multiply 30 by 7/4. The answer you get is 52.5. If you are confused, try more scale factor problems, and I suggest looking at Khan Academy. ^_^
Hope I helped!
YOU CAN ALSO DO THIS ANOTHER WAY that does not involve multiplying with fractions. With ratios, ORDER MATTERS. Whatever is mentioned first is x, and whatever is mentioned next is y. In this case, the standard ratio format is x:y. x=sugar and y=cake. Divide the ratio 30:4 by 4. You get 7.5:1 Multiply 1 by 7, because 1, 4, and 7 are the cakes. [You can apply "what you do to one side, you must do to the other" to rations, because ratios are just division problems and fractions too]. You must multiply 7.5 by 7 too. You get 52.5 for sugar. Don't forget units. Your teacher might let is slide, but when you get to higher grades, 52.5 as a number? This will be marked wrong. Express the answer with units, and in this case, 52.5g of sugar.
Hope I helped!
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