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Answer:
13 , 17 and 25 cm.
Step-by-step explanation:
Let the length of the first side be x cm.
Then the second is x+4 and the third is 2x-1 cm long.
As the perimeter = 55 cm we have the equation:
x + x + 4 + 2x - 1 = 55
4x + 3 = 55
4x = 52
x = 13 cm.
Answer:
3:7
Step-by-step explanation:
So to solve this problem, you have to understand what the ratio 1:4 and 2:3 means. The 1:4 ratio in the first equation means that for "each unit of alcohol" there is 4 of those units of water. So let's say I had 2 gallons of alcohol and mixed it with 8 gallons of water. This means for each gallon of alcohol, there is 4 gallons of water, or in other words a 1:4 ratio. This can be described as a percentage as well. For each 5 gallons there are 4 gallons of water, and 1 gallon of alcohol or <em>20%</em> is alcohol. So let's just say that x=alcohol and y=water, this means that:
where c is the total amount in the glass. This means that: 
Let's do the same thing to the second equation. the ratio means that for every 2 units of alcohol there are 3 units of water. This means for every 5 gallons of the mixture there is 2 units of alcohol which is 40%. In this case let's also say that j=alcohol and k=water. This means that:
and that:
.
So if we're going to add the two glasses, we simply add the two sides, and get:
. Now remember how can can express j and x in terms of c, since it's a certain percentage of c (the entire thing). This means that we get:
Now we can add like terms to get the equation:
. We can find how much 0.6c is to 2c by dividing the 2, in doing so we get that 0.6c/2c = 0.3, or in other words the 0.6c is only 30% of the final mixture, and since the 0.6c represents the alcohol in this mixture, that means that's the percentage of alcohol. To write this as a ratio, this means for every 3 units of alcohol, there is 7 units of water, because 3/10 = 30%.
Answer:
- <em>convert </em>the mixed fractions to improper fractions (where the numerator is greater than or equal to the denominator): multiply the whole number part by the fraction's denominator, add that to the numerator, write the result on top of the denominator.
- if the denominators are not the same, work out the common denominator and <em>rewrite </em>the fractions with the same denominators
- subtract by subtracting the numerators and writing the result over the denominator
- convert back to mixed fractions by dividing the numerator by the denominator, write down the whole number answer, write down the remainder above the denominator.
Example

convert to improper fractions:

common denominator = 3 × 5 = 15, so:

subtract:

convert back to mixed fractions:

Its a prime number because 29 goes in to 10 numbers