Question

You sell your bicycle to your friend for 65$ your friend gives you x five dollar bills and y ten dollar bills. There are a total of 9 bills. How many five dollar and ten dollars bills did your friend give you?

Answer 1

Answer:

There are $5$ five dollar bills and $4$ ten dollar bills.

Step-by-step explanation:

Given:

Selling price of bicycle $=\ 65$.

The friend gave $x$ five dollar bills and $y$ ten dollar bills.

Total number of bills $=9$.

To find: Number of five dollar bills and ten dollar bills the friend gave.

Solution:

The friend gave $x$ five dollar bills and $y$ ten dollar bills and the friend gave $9$bills in all.

So, $x+y=9$.

$\Rightarrow x=9-y ...(i)$

Selling price of bicycle $=\ 65$.

So, $5x+10y=65...(ii)$

Putting the value of $x$ from equation $(i)$ in equation $(ii)$.

$\Rightarrow 5(9-y)+10y=65$

$\Rightarrow 45-5y+10y=65$

$\Rightarrow 45+5y=65$

$\Rightarrow 5y=65-45$

$\Rightarrow 5y=20$

$\Rightarrow y=\frac{20}{5}$

$\Rightarrow y=4$

Now, putting the value of $y$ in equation $(i)$.

$\Rightarrow x=9-4$

$\Rightarrow x=5$

Hence, there are $5$ five dollar bills and $4$ ten dollar bills.