# Cowling’s rule is another function for determining the child’s dosage of a drug. For this rule, the formula     d= D(a+1)/24a) If a doctor prescribes 75 milligrams of Tamiflu for an adult,...

Cowling’s rule is another function for determining the child’s dosage of a drug. For this rule, the formula

d= D(a+1)/24

a) If a doctor prescribes 75 milligrams of Tamiflu

for an adult, then how many milligrams would she prescribe

for an eleven-year-old child using Cowling’s rule?

b) If a doctor uses Cowling’s rule to prescribe 600mg

of a drug to a child when she would prescribe

1000mg to an adult, then how old is the child?

jgeertz | College Teacher | (Level 1) Associate Educator

Posted on

Cowling's rule

`d=(D(a+1))/24`

where `d` = child's dosage

`a` = age of child in years

a) `d=(D(a+1))/24`

`d=(75(11+1))/24`

`d=(75(12))/24`

`d=900/24`

d=37.5 mg

b)  `d= (D(a+1))/24`

`600 = (1000 (a+1))/24`

`600= (1000(a) +1000)/24`

`` `600/1=(1000(a)+1000)/24`

cross multiply

`600(24)=1(1000(a)+1000)`

`14,400=1000a +1000`

subtract 1000 from both sides

`13,400 =1000a`

`` divide each side by 1000

`13.4 = a`

``The child is 13.4 years old.