SAT Mathematics Practice Test 7

Questions 39 and 40 refer to the following information.

Mosteller’s formula: A =

√{{\text "hw"}/60}

Current’s formula: A =

{4 + w}/{60}

The formulas above are used in medicine to estimate the body surface area A, in square meters, of infants and children whose weight w ranges between 3 and 30 kilograms and whose height h is measured in centimeters.

Question : 39 of 59

Marks: +1, -0

Based on Current’s formula, what is w in terms of A ?

w = 30A − 4
w = 30A + 4
w = 30(A − 4)
w = 30(A + 4)

Validate

Solution:

Current’s formula is

A = {4 + w}/30

. Multiplying each side of the equation by 30 gives 30A = 4 + w. Subtracting 4 from each side of 30A = 4 + w gives w = 30A – 4.

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