Practice math questions #1?

Question

I need help on the following problems, and all steps and formulas would greatly needed:

1) The body mass index (BMI) of a person 62 inches tall and weighing x pounds is given by 0.2x-2. A BMI of 30 or more is considered to be obese. For what weighs would a person 62 inches tall be considered obese?

2) Two angles are supplementary. The measure of the larger angle is 15 degrees more than twice the measure of the smaller angle. Find the angel measures.

Answer 1

1)

0.2x-2 = 30

    +2   +2

.2x = 32

/.2  /.2  

x = 160

2)

x + (2x + 15) = 180

3x + 15 = 180

3x = 165

x = 55

Answer 2

I know #2 - You know that x + y = 180   AND x=2y+15, therefore 2y+15+y=180 which also means 3y=165, which also means y=55.  And because y=55, x+55=180, therefore x=125.

The two angles are 55 degrees and 125 degrees.

With #1, are you saying the equation 0.2(x) -2 ... multiplying a negative two?

Answer 3

1) So you need to know when it would be more than 30. Set your formula equal to 30...

30= 0.2x-2

add 2 to each side

32=0.2x

divide each side by .2

160=x

so anyone over 160lbs is obese

2) Supplementary angles add up to be 180 degrees, so you want to know when the two angles will equal 180. Let x equal the smaller angle and the larger angle will be equal to 2x=15 (two times the smaller angle plus 15 degrees)

So the equation is 180= x+(2x+15)

simplify

180= 3x+15

subtract 15 from each side

165=3x

divide by 3

x=55

So your angles would be 55 and 125