Problema Solution
The quantity y is directly proportional to z. If y=12 when z=36, find the formula for y. As an
application for your formula, find what is y when z is 21.
Answer provided by our tutors
'y is directly proportional to z' means the formula for 'y' is 'y = k*z', where 'k' is a constant.
If y=12 when z=36 we can write:
12 = k*36
36k = 12 divide both sides by 36
k = 12/36
k = 1/3
The formula for y is:
y = (1/3)z
Now, we will find 'y' when 'z = 21' by plugging into the above fromula:
y = (1/3)*21
y = 7