Converting weight across systems to compute a dosage

The rate is per kilogram and the patient is in pounds, so the conversion comes first. ALEKS hands you the factor — the only decision is which way it points.

01 Worked Example Video

Every step of Converting weight across systems to compute a dosage explained on video. Pause anywhere; the embed scrolls independently of the page.

YOUTUBE

02 What This Looks Like on ALEKS

ALEKS randomizes the numbers each attempt, but the question shape stays the same. Here are three example versions you might see.

A bigger animal

A dog weighs 60 lb. Medicine is dosed at 12 mg for each kilogram of mass.

How much medicine? Use 1 lb = 0.45 kg. Type just the number.

Just the conversion

A patient weighs 80 lb.

What is that in kilograms? Use 1 lb = 0.45 kg. Type just the number.

The other direction

An animal weighs 27 kg.

What is that in pounds? Use 1 lb = 0.45 kg. Type just the number.

Heads up: Your ALEKS version will use different numbers. The numbers in the practice below are different too — that way you're exercising the move, not memorizing one answer.

03 The Rule

read the factor as ALEKS writes it “1 lb = 0.45 kg” means each pound IS 0.45 kg

then dose = kilograms × mg per kg the rate names the unit it needs

Written that way, the conversion is a multiplication: 45 pounds, each worth 0.45 of a kilogram. Reaching for a remembered “1 kg is about 2.2 lb” and dividing gets you close, but ALEKS supplies its own figure and expects you to use it.

Common slips

(1) Divided instead of multiplying. The factor says one pound IS 0.45 kg, so multiply. Dividing 45 by 0.45 gives 100 kg, heavier than the animal is in pounds, which cannot be right. (2) Applied the rate to pounds. The rate says per kilogram; using pounds overdoses by more than double. (3) Used a remembered factor. ALEKS gives you one and says not to round. Use theirs.

04 Practice — Step by Step

Convert, then apply

Ravi’s dog needs medication. The dog weighs 45 lb. The medicine is measured as 8 mg for each kilogram of the animal’s mass.

How much medicine should be given?

Use 1 lb = 0.45 kg and do not round any computations.

Step 1

Multiply or divide?

You are told 1 lb = 0.45 kg and the dog weighs 45 lb. Which gets you kilograms?

Step 2

Pounds to kilograms

45 × 0.45. Keep every decimal.

Step 3

Apply the rate

20.25 kg at 8 mg per kilogram.

Step 4

The error to avoid

What would you have got applying the rate to pounds instead?

Q9 Q11

Converting weight across systems to compute a dosage

Why the unit matters more here than anywhere