Question

Mary Jo spends $2,300 to buy stock in two companies. She pays $19 a share to one of the companies and $24 a share to the other. If she ends up with a total of 100 shares, how many shares did she buy at $19 a share and how many did she buy at $24 a share?

She bought ____ shares at $19 and ___ shares at $24.

Answer 1

Mary Jo bought 20 shares at $19 a share and 80 shares at $24 a share.

Explanation:

Let's use algebra to solve the problem. Let x be the number of shares Mary Jo buys at $19 a share, and y be the number of shares she buys at $24 a share.

We know that Mary Jo spends a total of $2,300, so we can write the equation:

19x + 24y = 2300

We also know that she ends up with a total of 100 shares, so we can write the equation:

x + y = 100

Now we have two equations with two variables, which we can solve using substitution or elimination.

Let's use substitution. Solve the second equation for x:

x = 100 - y

Substitute this expression for x in the first equation:

19(100 - y) + 24y = 2300

Simplify and solve for y:

1900 - 19y + 24y = 2300

5y = 400

y = 80

So Mary Jo bought 80 shares at $24 a share.

To find the number of shares she bought at $19 a share, substitute y = 80 in the second equation:

x + 80 = 100

x = 20

Therefore, Mary Jo bought 20 shares at $19 a share.

In summary, Mary Jo bought 20 shares at $19 a share and 80 shares at $24 a share.