Question

A grain of sand weighs about 1 x 10 g.
Researchers at the University of Hawaii
estimate there are 7.5 x 108 grains of
sand on all the beaches of Earth. How
much do all of these grains of sand
weigh?
O A. 7.5 x 10 g
OB. 8.5 x 10g
O c. 7.5 X 102 g
O D. 8.5 X 102 g​

Answer 1

Answer:

$7.5\cdot 10^9 g$

Step-by-step explanation:

In this problem, we are told that the mass of 1 grain of sand is:

$m=1\cdot 10^1 g$

The total mass of N grains of sand will be therefore

$M=Nm$

where

N is the number of grains of sand

M is the total mass

Here we have a number of grains of sand equal to

$N=7.5\cdot 10^8$

Therefore, the total mass of the grains of sand is:

$M=(7.5\cdot 10^8)(1\cdot 10^1 g)=7.5\cdot 10^9 g$