Question

3. If x is directly proportional to y and x = 4.5 when
y = 3, find
(i) an equation connecting x and y,
(ii) the value of x when y = 6,
(iii) the value of y when x = 12.​

Answer 1

Step-by-step explanation:

Given that,

x is directly proportional to y

Therefore,

\begin{gathered}x \propto y \\\\x = ky ------ eqn\ 1\end{gathered}

x∝y

x=ky−−−−−−eqn 1

{x = 4.5}x=4.5 when {y = 3}y=3

Substitute in eq 1

{4.5=k×3}4.5=k×3

{k=1.5}k=1.5

Substitute k = 1.5 in eq 1

{x = 1.5y}x=1.5y

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(ii) when {y=6}y=6

{x=1.5×6}x=1.5×6

\huge\bold\orange{{x=9}}x=9

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(iii) when {x=12}x=12

{y=1.5×12}y=1.5×12

\huge\bold\red{{y=18}}y=18

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