Directly and Inversely Proportional Equations

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

If s varies directly as t and inversely as v, then which of the following equations describes the relation among the three variables s, t, and v?

• s = k / tv

• s = kv / t

• 1/s = kt/ v

• s = kt / v

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

Which of the following represents the statement, m varies directly as j.

• . j = km

• m = k/j

• k = j/m

• m = kj

If p varies directly as q and p = 18 when q = - 6, then k is __________.

• -3

• -1/3

• 1/3

• 3

The amount (A) of money raised in a concert to the number (n) of tickets sold is an example of what kind of variation?

• direct

• inverse

• joint

• combined