Expert: Chanda Walker - 3/10/2009

Question
I found these online and answered them wrong. Please help me solve them. Note: They are not homework from school.

Meghan has 100 dollars more than Andrew has. After Meghan spends 20 dollars on groceries, she will have five times as much money as Andrew. How much money does Andrew have?

At a local theater, adult tickets cost $8 and student tickets cost $5. At a recent show, 500 tickets were sold for a total of $3,475. How many adult tickets were sold?

Mr. Chen wants balloons to decorate his kindergarten classroom. Each package contains 12 balloons. If he wants at least 5 balloons at each of the 10 tables, how many packages should he buy?

Fred invested $350 in the stock market. The value of his investment increased by 25%, and then later
decreased by 40%. How much did the investment decrease in value from the time he first invested?

In a class, 10 students are receiving honors credit. This number is exactly 20% of the total number of students in the class. How many students are in the class?

Answer
It's ok even if they are homework from school but I like to have people try to the problems before I help them through them.

Meghan:

M = A + 100

M - 20 = 5*A

(A + 100) - 20 = 5A
80 = 4A
A = 20

Andrew has $20

Theater:

A = 8
S = 5
x + y = 500
Ax + Sy = 3475

A(500 - y) + Sy = 3475
500*8 + (-8 + 5)y = 3475
-3y = -525
y = 175

x = 325

Mr. Chen:
minimum number of balloons: 50
balloons in a package: 12
number of packages needed:  50/12 = 4.2  Buy 5 packages

Fred:
$350*(1.25) = $437.5
$437.5*(.4) = $175
$437.5 - $175 = $262.5
$300 - $262.5 = $37.50

He lost $37.50

Honors students:
x*.2 = 10
x = 50

There are fifty students.