Question

Directions: Type the correct answer in the box. Use numerals instead of words.

A scientist reviews her data to find the measures of central tendency using a calculator
She finds the average mass of an adult brown bear is about 1.36E5 grams, and the average mass of a beetle fly is approximately
0.61E2 grams
She also found the sum total of her data using a calculator. The total brown bear population in the world is approximately 2E5, and
the total beetle fly population is approximately 7E10.
times more than the total mass
Rounded to the nearest whole number, the total mass of all living beetle flies is approximately
of all living brown bears.
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Answer 1

157 times

Explanation:

The total mass of a population is found by multiplying the individual mass by the population. This is true for both beetle flies and brown bears. Once we know the population masses, we can find their ratio.

fly mass = (0.61E2 g/fly)(7E10 flies) = 4.27E12 g

bear mass = (1.36E5 g/bear)(2E5 bears) = 2.72E10 g

Then the ratio of fly mass to bear mass is ...

(4.27E12 g)/(2.72E10 g) ≈ 1.57E2

The mass of beetle flies is about 157 times the mass of brown bears.

_____

Additional comment

The E used in the numbers above is a form of scientific notation used by computers and calculators to mean ×10^. That is, ...

0.61E2 ≡ 0.61×10^2

The usual rules of exponents apply:

(10^a)(10^b) = 10^(a+b)

(10^a)/(10^b) = 10^(a-b)

Moving a decimal point is equivalent to multiplying or dividing by a power of 10:

1.0×10^1 = 10.×10^0