Question

the number of red blood cells per cubic millimetre of blood is approximately 5.5 million.If the average body contains 5 litres of blood what is the total number of red cells in the body ? (1litre=1,00,000mm^3)
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Answer 1

Step-by-step explanation:

hloo dear,

∵1 litre = 100,000 mm³

∴5 litre = 5×100,000 mm³

               =500,000 mm³

∵1 mm³= 5.5 million

∴500,000 mm³= 500,000×5.0

                           =2750000 million answer

thank u.

Answer 2

The total number of red cells in the body is 27.5×10⁵ million or 27.5×10¹¹

First we make sure that different units representing the same physical quantity are converted to a same unit.

So, litres is converted to mm³ as the concentration of red blood cells are given per cubic mm.

As, 1L = 100000mm³

So, 5L of human blood would have volume = (5 × 100000) mm³ = 500000mm³ = 5×10⁵ mm³

From the question, we can say that 5.5 million RBC = 5.5×10⁶ RBC are present per 1 mm³ volume of blood.       [1 million = 10⁶]

So, 1 mm³ volume of blood has 5.5×10⁶ RBC

So, 5×10⁵ mm³ (vol. of blood in human body) has ( 5.5×10⁶ × 5×10⁵) RBC

= (5.5×5 × 10¹¹) RBC               [As, xᵃ × xᵇ = x^(a+b)]

= 27.5×10¹¹ RBC

= 27.5×10⁵ million RBC          [As, xᵃ ÷ xᵇ = x^(a-b)]