Direct Variation or Inverse Variation

Suppose y varies inversely with x.
If y = 150 when x = 2, find y when x = 25.

• 300

• 75

• 1,875

• 12

The number of kilograms of water in a person’s body varies directly as the person’s mass.  A person with a mass of 90 kg contains 60 kg of water.  How many kilograms of water are in a person whose mass is 75 kg?

• 50 kg water

• 72 kg water

• 94 kg water

• 150 kg water

The volume V of a gas kept at a constant temperature varies inversely as the pressure p.
If the pressure is 24 pounds per square inch, the volume is 15 cubic feet.
What will be the volume when the pressure is 30 pounds per square inch?

• 8 cubic feet

• 10 cubic feet

• 12 cubic feet

• 14 cubic feet

What relationship does the table represent?

• Direct

• Inverse

• Neither

This type of variation states that the two quantities increase at the same time or decrease at the same time.

• Direct Variation

• Inverse Variation

• Joint Variation

• Combined Variation

The cost c varies directly as the number of n pencils is written as

• c = kn

• k = cn

• n = k/c

• c = k/n

The speed r of a moving object is inversely proportional to the time t travelled is written as

• r = kt

• r = k/t

• t = kr

• t = r/k

Which of the following types of variation states that the decrease of one quantity results to the increase of the other quantity?

• Direct Variation

• Inverse Variaton

• Joint Variation

• Combined Variation

If y varies directly as x and y = 24, when x = 3, then what is the value of k?

• 4

• 6

• 8

• 72

Which of the following phrases illustrate an inverse variation?

• The area of the wall to the amount of paint used to cover it

• The amount of money raised in a concert to the number of tickets sold

• The time a teacher spends in checking papers to the number of students

• The age of a used car to its resale value