word problems

Question

The standard guideline for fluid intake recommends that a 10-20kg child should have 1000mL of fluid plus 50 mL for each kilogram of body weight over 10 kg per day.  How many 8-ounce glasses of fluid should a 39 pound child have each day?

Answer 1

oz is best dealt with by converting mL into L, as 1L is 33.8 oz

 

First, convert the childs weight, 39 pounds, into kg. which is 17.7kg

 

second, subtract 17.7kg from 10kg, which is 7.7kg. this is done because we have the extra piece of data about adding 50mL for each kg over the babies kg.

 

third convert 50mL into L, which is .05 L, and multiply this with the 7.7kg to get the extra fluid amount over 10 kg. which is .385 L/kg. we know 1L equals 33.8oz, so we can multiply 33.8 by .385 to get L into oz, which is 13oz.

 

fourth, we have a child between 10-20kg at 17.7, so the child needs 1L(1000mL) or 33.8oz of water, plus the 13 oz for the baby being 7.7kg over 10. 

 

so in total we have 33.8oz plus 13oz to equal 46.8oz, and then divide by 8oz to get the number of glasses the child needs, so 46.8oz/8oz to be 5.85 glasses.