Question

Equation of Direct Proportion)
If y is directly proportional to x and y = 12 when x = 4, find
(i) an equation connecting x and y,
(ii) the value of y when x = 8,
(iii) the value of x when y = 21.
portional to x,​

Answer 1

Gɪᴠᴇɴ :-

• y is directly proportional to x
• y = 12 when x = 4

Tᴏ Fɪɴᴅ :-

• (i) an equation connecting x and y,
• (ii) the value of y when x = 8,
• (iii) the value of x when y = 21.

Sᴏʟᴜᴛɪᴏɴ :-

(i) an equation connecting x and y :-

Given That, y is directly proportional to x .

So,

⟿ y ∝ x

⟿ y = kx (where k is any constant No.) . (Ans.)

_____________________

(ii) the value of y when x = 8 :-

Now, Given That, y = 12 when x = 4.

So,

⟿ y = kx

⟿ 12 = k * 4

⟿ k = (12/4)

⟿ k = 3 .

Hence, when x = 8

⟿ y = k * x

⟿ y = 3 * 8

⟿ y = 24 (Ans.)

_____________________

(iii) the value of x when y = 21 :-

⟿ y = kx

And, we have k = 3.

So,

⟿ 21 = 3 * x

⟿ x = (21/3)

⟿ x = 7 (Ans.)

_____________________

Answer 2

Answer:

Please find attachment

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