How much money would you make if you acquired $1\%$ of all iPhone sales?

Question

Me and a friend had a dispute over the answer to this question today. The scenario is:

If you got $1\%$ of iPhone sales (Assuming $\$900$ in Canadian Dollars), how much would you make over Ten Million ($10{,}000{,}000$) sales?

We have two answers, and each believe we are correct.

I believe the following:

$1\%$ of $900$ is $9$. $9$ times $10{,}000{,}000$ equals $90{,}000{,}000$. So you would make $\$90{,}000{,}000$ over Ten Million Sales. Alternatively, you could do $900\times 10{,}000{,}000 = 9{,}000{,}000{,}000$ (Nine Billion) and $1\%$ of $9{,}000{,}000{,}000$ is Ninety Million Dollars.

My friend believes that the answer would be $81{,}000{,}000$ using the standard steps to calculate percentage. Although I believe he got the math wrong, (Multiplying by $0.09$ instead of $0.01$) he insists he is correct.

Who is correct between us?

Answer 1

$$Percent \times price \times units = 1\% \times $900 \times 10,000,000 = $90,000,000$$

Answer 2

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Cost per iPhone: $900

Quantity sold: 10,000,000

Retained earnings: 1% = 0.01

$$c := \$900$$ $$\space\space\space q := 10,000,000$$ $$\space\space\space p := 0.01$$

$$c \cdot q \cdot p = \$900 \times 10,000,00 \times 0.01 = \$90,000,000$$

Answer 3

Simply find the $1\%$ of $\$900$ i.e.,

$$\dfrac{x}{900}=\dfrac{1}{100}$$ $$x=\dfrac{900}{100}$$ $$x=9$$

And simply multiply by Ten Million $(10,000,000)$ $$9\times10,000,000=\$90,000,000$$ I hope it' ll help.