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

To find the number of human cells in a newborn baby, we start with the mass of the baby, which is 3.5 kg. Since we need this value in grams for calculations, we convert it as follows:

$3.5 ext{ kg} = 3.5 imes 1000 ext{ g} = 3500 ext{ g}$

Next, we take the mass of a single human cell, which is given as approximately $2.7 imes 10^{-11}$ grams.

Now, we estimate the number of cells by dividing the total mass of the baby by the mass of a single cell:

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

Calculating this gives us:

$\frac{3500}{2.7 \times 10^{-11}} \approx 1.296 \times 10^{14}$

To express this in standard form and rounding to 2 significant figures, we have:

$1.3 \times 10^{14}$

Therefore, the estimated number of human cells in a newborn baby is approximately 1.3 × 10^{14}.