MATH GRADE 9 PAHELP PO CHOICES

12) If p varies jointly as r and the square of t, and p is 60 when r is 5 and t is 2, what is the value of

the constant of variation?

A. k = 3

B. k = 4

C. k = 5

D. k = 6


13) y varies jointly as x and z. If the constant of variation is 7 and x is 3 and z is 4, find

the value of y.

A. 14

B. 21

C. 56

D. 8

14)m varies jointly as p and the square of q. If m is 35 when p is 7 and q is 1, find p

when m is 225 and q is 3.

A. p = 3

B. p = 4

C. p = 5

D. p = 6


15)The volume of a rectangular prism varies jointly as its length, width and height.

If a rectangular prism with length of 5 cm, width of 7 cm and a height of 2 cm has a

volume of 70 cubic centimeters, what is the volume of the other rectangular prism if its length

is 3cm, width is 10 cm and its height is 4cm?

A. 753

B. 1203

C. 1503

D. 2253


16) Which of the following equations illustrates combined variation?

A. V = lwh

B. A = 2

C. z = km/hr



17) Which of the following situations represents combined variation?

A. The salary varies directly with the number of hours worked.

B. The force in carrying a log varies inversely with the number of people carrying the log.

C. The interest varies jointly with the rate and time.

D. The electrical resistance of a wire varies directly as its length and inversely as the square of

its diameter


19) w varies jointly as x and y and inversely as z. If w is 15 when x is 3, y is 6 and

z is 8, find w if x is 15, y is 12 and z is 20.

A. 150

B. 120

C. 60

D. 30



18) If p varies directly as r and inversely as t, and p is 9 when x is 6 and t is 12, what is the value of

the constant of variation?

A. k = 18

B. k = 12

C. k = 10

D. k = 4


20) The number of minutes to assemble a puzzle varies directly as the number of puzzle

pieces and inversely as the number of people working on the puzzle. If it takes 30

minutes for 5 people to assemble a 100-pc puzzle, how many puzzle pieces did 20

people assembled if it took them 75 minutes to finish the puzzle?

A. 300 pieces

B. 500 pieces

c. 1000 pieces

D. 5000 pieces

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