Question

a student has some $1 bills and $5 bills in his wallet. he has a total of 15 bills that are worth $47. How many of each type of Bill does he have. (using algebra, substitution to solve a problem)

Answer 1

The student would have 8 $5 bills and 7 $1 bills because 5*8=40 and 7*1=7 and adding them together makes 47! Hope that helps!
 

Answer 2

Answer:  The student has 7 $1 bills and 8 $5 bills.

Step-by-step explanation:  Give that a student has some $1 bills and $5 bills in his wallet. He has a total of 15 bills that are worth $47.

We are to find the number of each type of bills that he has.

Let m and n represents the number of $1 bills and $5 bills respectively.

Then, according to the given information, we have

$m+n=15\\\\\Rightarrow m=15-n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

and

$1\times m+5\times n=47\\\\\Rightarrow m+5n=47\\\\\Rightarrow 15-n+5n=47\\\\\Rightarrow 4n=47-15\\\\\Rightarrow 4n=32\\\\\Rightarrow n=\dfrac{32}{4}\\\\\Rightarrow n=8.$

From equation (i), we get

$m=15-8=7.$

Thus, the student has 7 $1 bills and 8 $5 bills.