A newborn baby has an approximate mass of 3.5 kilograms - OCR - GCSE Maths - Question 3 - 2018 - Paper 6

To find the estimated number of human cells in a newborn baby, we can use the following steps:

1. Convert the Mass of the Baby to Grams:

   A newborn baby has a mass of 3.5 kilograms, which can be converted to grams:

   $3.5 ext{ kg} = 3500 ext{ g}$

2. Determine the Mass of a Single Cell:

   The mass of a human cell is given as $2.7 \times 10^{-11}$ grams.

3. Calculate the Number of Cells:

   The number of human cells can be estimated using the following formula:

   $\text{Number of cells} = \frac{\text{Mass of baby}}{\text{Mass of cell}}$

   Substituting the values:

   $\text{Number of cells} = \frac{3500 \text{ g}}{2.7 \times 10^{-11} \text{ g}}$

   Performing the calculation:

   $\text{Number of cells} \approx 1.2962963 \times 10^{14}$

   To express this in standard form, we round to two significant figures:

   $\approx 1.3 \times 10^{14}$

Thus, the estimated number of human cells in a newborn baby is approximately 1.3 x 10^14.