Question

If x varies directly as y, and x = 200 when y = 11, find y when x = 500. Please algebraic solution :) thanks!

Answer 1

y = 27.5

Explanation:

We know that directly proportional equations usually come in the format of

y = k × x where 'k' is the constant. In this problem we are presented with a directly proportional questions asking us to find y when x= 500 considering that y varies directly with x and x = 200 when y = 11. So let's substitute in the values

→ y = k × x

⇒ Substitute in the first set of values which is x = 200 and y = 11

→ 11 = k × 200

⇒ Divide both sides by 200 to isolate 'k'

→ 0.055 = k

Now we know that the constant is 0.055 we can substitute the second set of values in,

→ y = 0.055 × x

⇒ Substitute in the second value which is x = 500

→ y = 0.055 × 500

⇒ Simplify

→ y = 27.5

If y varies directly with x and x = 200 and y = 11, the value of y when x = 500 is 27.5

Answer 2

x ⠀⠀200⠀⠀ ⠀500

y⠀⠀⠀ 11⠀⠀⠀⠀⠀a

As x directly varies with y

200 × a = 500 × 11

a = 5/2 × 11 = 27.5