JOINT VARIATION

Write the given statement in a mathematical equation.

r varies jointly as s and w

• r = ksw

• $r=\frac{ks}{w}$

• $r=\frac{kw}{s}$

• w = ksr

Write the given statement in a mathematical equation.

Interest (I) varies jointly as the principal (P) amount deposited, and the rate (r) and time (t) of the deposit.

• I = kPrt

• P = kIrt

• T = kPIt

• r = kPIt

Solve for the constant of variation, k.

y varies jointly as x and z.   x = -2 when y = 24 and z = -4

Solve for the constant of variation, k.

z varies jointly as x and y.   x = 3, when y = -8 and z = 6.

y varies jointly as x and z. If y = -40 when x = -2 and z = -1, what is the variation equation?

• y = -2xz

• y = -40xz

• y = 20xz

• y= -20xz

The variable x is in joint variation with y and z. When the values of y and z are 4 and 6, respectively, x is 72. What is the value of x when y = 2 and z =8?

• 32

• 48

• 64

• 96

A is in joint variation with B and square of C. When A = 144, B = 4 and C = 3. Then what is the value of A when B = 6 and C = 4?

• 12

• 36

• 384

• 96

z varies jointly with x and y. If x = 2, y = 3 and z = 18, find z when x = -6 and y = 2.

• -36

• -10

• -24

• -12

z varies jointly with x and y. If x = 5, y = -1, and z = 10. Find z when x = -1 and y = 7.

• 14

• 7

• -21

• -7

If y varies jointly with the product of x and z, and y = 1000 when x = 10 and z = 20, find y when x = 8 and z = 10.

• 100

• 300

• 200

• 400