Question

Write the equation that represents the relationship between the given two quantities x and y in the following table:

x	2	4	7	8	11
y	5	10	17.5	20	27.5

• A. y = 3.5x
• B. y = 2x
• C. y = 1.5x
• D. y = 2.5x

Answer 1

The correct option is D y = 2.5x

x	2	4	7	8	11
y	5	10	17.5	20	27.5

From the table, we can observe:
$\text{When x = 2, y =}$$2.5\times 2=5$
$\text{When x = 4, y =}$$2.5\times 4=10$
$\text{When x = 7, y =}$$2.5\times 7=17.5$
$\text{When x = 8, y =}$$2.5\times 8=20$
$\text{When x = 11, y =}$$2.5\times 11=27.5$

So, there exists a proportional relationship between x and y.

The relationship can be shown as:

$\frac{5}{2}=\frac{10}{4}=\frac{17.5}{7}=\frac{20}{8}=\frac{27.5}{11}=2.5$

$\text{∴ Output}=2.5\times \text{Input}$

So, the equation will be y = 2.5x.