TBR test 1 biological sciences q 11

[2010premed]

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An estimate of the BMR can be determined from the following simple equations:
For men: BMR = 1.0 kcal/kg/hr
For women: BMR = 0.9 kcal/kg/hr

What would be the difference in the energy consumed by the BMRs of a 70-kg man and a 70-kg woman in a 24-hour period?


A: 168 kcals


this is how they do it:
Man: 70 kg x 24 hr x 1.0 kcals/kg•hr = 1680 kcals

Woman: 70 kg x 24 hr x 0.9 kcals/kg•hr = 1512 kcals

Difference: 1680 kcals - 1512 kcals = 168 kcals.

How would you know to multiply the 3 numbers?? I would divide since it says 1kcal/kg/hr

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[brownhamster]

don't you have to multiply to cancel out the units

 

[baronz]

Just look at the solution. The units in the numerator has to cancel the units in the denominator to ultimately get only kcal.

Or you can simplify and just say 1kcal/kg for men and .9kcal/kg for women. So you get 70kcal for a 70kg man and you get 63kcal for a 70kg woman. Then you say thats 70kcal/hr and 63kg/hr. So you multiply by 24 to get a days worth and then subtract.

 

[2010premed]

thx, I think there's also an error b/c in the question they write the units differently than in the explanation