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The ratio x:y is equal to is 2 : 5, and y is 80% of z. Write an equation to represent the proportional relationship between x and z.

User Kajetan Abt
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1 Answer

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Answer:

z = 3.125 * x

Explanation:

since y is 80 percent of z, we can represent it in the form of a ratio as 80:100.

Simplify it down: 80:100 = 8:10 = 4:5

therefore x:y = 2:5
and y:z = 4:5

"y" is common in both of these ratios. Therefore we now have to make the value of Y same in both of the ratios. Therefore we find the least common multiple of both the y values which is 5 and 4. It is 20.

Now we make the value of y in both the ratios 20. So we need to multiply 5 in 2:5 by 4. Since we multiplied one of the values by 4 we have to multiply the other one as well (2*4). Now our new ratio for x:y is 8:20. Do the same for the other ratio. the other ratio is 4:5. the y value here is 4. 4 needs to be multiplied by 5 to become 20. Therefore multiply 4 by 5 and multiply 5 by 4. our new ratio for y:z is 20:25

As you can see both the y values are similar now.

x:y = 8:20

y:x = 20:25

therefore we can now write x:y:z as 8:20:25

that also means that x:z is now 8:25.

Now we know that when x is 8 z is 25. in this case. 8 and 25 are directly proportional.

therefore we can write an equation as
25 = k*8
k = 25/8

k = 3.125

therefore z = 3.125 * x

User Razib Mollick
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