Alison had a BMI of 23 at conception, & her doctor says her target weight by the end of pregnancy should be 165-175 pounds. How much did she weigh at conception?

• A. 120 pounds.
• B. 130 pounds.
• C. 140 pounds.
• D. 50 pounds.

Answer: (C)

Verified step by step guidance

1. Understand that BMI (Body Mass Index) is calculated using the formula: $\mathrm{BMI}=\frac{\mathrm{weight\; (kg)}}{{\mathrm{height\; (m)}}^2}$. To find weight, we rearrange it to: $\mathrm{weight\; (kg)}=\mathrm{BMI}\times {\mathrm{height\; (m)}}^2$.
2. Recognize that Alison's BMI at conception is 23, and we need to find her weight at that time. However, we need her height to calculate weight from BMI.
3. Use the target weight range (165-175 pounds) and the BMI formula to estimate Alison's height. Convert pounds to kilograms (1 pound ≈ 0.4536 kg) for calculation consistency.
4. Calculate height by rearranging the BMI formula using the target weight and BMI range, then use this height to find Alison's weight at conception by plugging BMI = 23 back into the formula.
5. Convert the calculated weight from kilograms back to pounds to find Alison's weight at conception and compare it with the given options to identify the correct answer.