Practice!

Sample Problem

When you visited planet M&M, you notice that 8 hulus of M&Ms is approximately equal to 97 mups. a)Use this information to find a linear model that relates mups y to hulus x.

(A) y=1.515625x2

(B) y= 12.125x

(C) y=776/x

(D) y=6208/x2

 

b)Using this linear model, find the number of mups in 18 hulus.

13968

.673611

218.25

43.1

 

c)How many mups are in 120 hulus?

21825

1455

6.4666667

.43111111

Solution

a)Choices (A) and (D) are not linear (the x term is squared).

Linear models represent y’s that are directly proportional to x, not inversely proportional;

therefore, the only linear model (also, by definition a direct variation model) that makes

8 hulus=97 mups is choice (B), where 12.125=k.

The correct linear model is y=12.125x where y is the number of mups and x is the number of hulus.

b)f(x)=12.125x, f(18)= 12.125(18)=218.25

c)f(120)=12.125(120)=1455