Question

Dave bowers collects u.s. gold coins. he has a collection of 50 50 coins. some are​ $10 coins, and the rest are​ $20 coins. if the face value of the coins is ​$ 740 740​, how many of each denomination does he​ have?

Answer 1

For this case, the first thing we must do is define variables.

We have then:

x: number of $ 10 coins

y: number of $ 20 coins

We now write the system of equations that models the problem:

$x + y = 50$

$10x + 20y = 740$

The graphical solution (see attached image) is given by the intersection of the equations.

We have then:

 $x = 26$

$y = 24$

Answer:

Dave has:

26 $ 10 coins

24 $ 20 coins