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Calculation Body Mass

Calculating body-mass index (BMI) is a way to gauge whether a person should lose weight. Doctors recommend that body-mass index values fall between 19 and 25. The formula for Body mass index B is B=705w/h^2, where w is weight in pounds and h is height in inches. A patient is 6ft 2 in tall. What should his or her weight be to have a body mass index of 25? (Round to the nearest whole pound) 

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Parviz F. | Mathematics professor at Community CollegesMathematics professor at Community Colle...
4.8 4.8 (4 lesson ratings) (4)
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 Ok:
 
h = 6ft, 2 in = 6* 12" + 2 = 74"
 
    W is unknown and has to be evaluated.
 
     750 w / 742 = 25
 
       w = (742 * 25 )/ 705 = 194.
 
    Thank you Jim . I took 750 for 705.
George T. | George T.--"It's All About Math!"George T.--"It's All About Math!"
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Theresa:
 
Per your formula, B=(705w)/h2, where w=weight in pounds and h=height in inches.
 
From the info provided, we know that B=25 and h=74 inches (6ft * 12 inches per foot + 2 inches).
 
Substituting these values in the formula, we get:  25=(705w)/(74*74)
                                                                       25=705w/5476
 
Now, solving for w, we get w=(25*5476)/705=194.18 pounds (rounded to nearest hundredth).
 
Hope this helps.
 
George T.
Jim S. | Physics (and math) are fun, reallyPhysics (and math) are fun, really
4.7 4.7 (142 lesson ratings) (142)
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Solving for w gives:
 
w=Bxh/705
 
Since you were given that:
B=25
h=74"
then w=25x(742)/705= 194 lbs
 
Robert J. | Certified High School AP Calculus and Physics TeacherCertified High School AP Calculus and Ph...
4.6 4.6 (13 lesson ratings) (13)
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B=705w/h^2
Solve for w,
w = Bh^2/705 = 25(6*12+2)^2/705 = 194.2 lb <==Answer
Brad M. | Professional Tutor: Ultra Streamlined Math - Physics - AccountingProfessional Tutor: Ultra Streamlined M...
4.9 4.9 (218 lesson ratings) (218)
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Hey Theresa -- one BMI that's easy to work with is 70" (5ft 10in)  at 140lb = 20 BMI ... 30 BMI at 70" thus 210lb ... 25 BMI "in-between" at 175lb ... every 1" change is about 1.5% => means weight must change 3% (double the ht change since h^2) ==> 6'2" is 4" or 6% change, wt change 12% or 20lb to ~195lb. CHECK: BMI = 700*200/74^2 ~ 140000/(5200+300) ~140k/55k ~28/11 ~25 ... Regards, ma'am :)