Question

The variable y varies directly as x When x= 20. y= 12. What is the value of y when x= 15?OA 7OB. 9Ос. 18OD. 25

Answer 1

"The variable y varies directly as x."

For this type of condition, we can just interpret this as getting the missing value through ratios and proportions.

We get,

`\text{ 20 : 12 = 15 : y}`
`\text{ 20 : 12 = 15 : y }\rightarrow\text{ }\frac{\text{ 20}}{\text{ 12}}\text{ = }\frac{\text{ 15}}{\text{ y}}`
`\text{ (20)(y) = (15)(12)}`
`\text{ 20y = 180}`
`\text{ }\frac{\text{20y}}{20}\text{ = }\frac{\text{180}}{20}`
`\text{ y = 9}`

Therefore, at x = 15, y = 9.

The answer is letter B.