Answer:
We know that for a human body 9.3% of its total mass is hydrogen.
Now we have a person with a mass of 140 lb.
Then we have that the 100% of the mass is 140lb, the 9.3% of this is hydrogen.
We can write:
9.3% = X
100% = 140lb
We want to find the value of X (mass of hydrogen)
Then we can take the quotient of these two equations to get:
(9.3%/100%) = X/140lb
Now we can isolate the variable X to get:
(9.3%/100%)*140lb = X = 13.02 lb
So this person has about 13.02 lb of hydrogen in his/hers body.
