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

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?

• Clearly you are correct. Your friend used the wrong percentage. – Parcly Taxel Oct 18 '16 at 4:32
• Not only that, but your friend did the wrong way wrong (unless it was a typo). Using 0.09 instead of 0.01 will yield 810,000,000 and not 81,000,000. – tilper Oct 18 '16 at 5:18
• "[...] using the standard steps to calculate percentage." Can you show these "standard steps" he did? Did he just take $9\%$ of the revenue? If so, have him explain how $9\% = 1\%$. – Therkel Oct 18 '16 at 13:44

$$Percent \times price \times units = 1\% \times 900 \times 10,000,000 = 90,000,000$$
Cost per iPhone: $900 Quantity sold: 10,000,000 Retained earnings: 1% = 0.01 $$c := \900$$ $$\space\space\space q := 10,000,000$$ $$\space\space\space p := 0.01$$ $$c \cdot q \cdot p = \900 \times 10,000,00 \times 0.01 = \90,000,000$$ 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.