2 × 10^12 red blood cells have a total mass of 90 grams. Work out the average mass of 1 red blood cell.
Give your answer in standard form.

2×10¹² cells → 90 g

mass of 1 red blood cell : 90÷(2×10¹²) = 45×10^-12 g = 4.5×10^-11 g

$70.47

Step-by-step explanation:

Since the cost of the aquarium with the 15% discount is $59.90 then $59.90 is 85% of the original price. Remember 100-15=785. To find the original price set up a proportion with these values:

Solve for the original price by cross multiplying numerator with denominator.

x(85) = 59.90(100)

85x = 5990

x= $70.47