Question

If y varies directly as x and z, and Y=40 when x =5 andz = 4, find y when x=2 and z = 1

Answer 1

Answer: When x=2 and z = 1, then the value of y =4.

Step-by-step explanation:

Given: y varies directly as x and z i.e. $y\ \alpha \ xz$

$y=k(xz)$      (i) , where k is the proportionality constant.

Put  Y=40 ,x =5 and z = 4, then we get

$40=k(5\times4)\\\\\Rightarrow\ k=\dfrac{40}{20}\\\\\Rightarrow\ k=2$

Required equation: $y=2(xz)$  [Put value of k in (i)]

Now put x=2 and z = 1, then we get

$y=2(2\times1)=2(2)=4\\\\\Rightarrow\ y=4$

Hence, when x=2 and z = 1, then the value of y =4.