VARIATIONS 1

x is directly proportional to y. x=40 and y=2. Find x while y=13.

solution

x ⍺ y

x = k y …….. (i)       [we put =k to replace the proportionality sign ⍺]

x=40, y=2, k=?

40 = k x 2        

40 =  2k  

      

²⁰40 =    ¹2k

   ₁2           2₁        

k = 20.

Now k=20, y=13, x=?

from( i)

x = k y

x = 20 x 13

x = 260.

Hence x=260

 TRY THIS…………………………..

x is directly proportional to y. x=42 and y=6. Find x while y=11.