i need help with math problem there are....?

Question

1. 250 deposited in bank at 8% annual interest, compounded annually. what balance after 3 year?
2.a test has 42 questions. questions are worth 2 points and 4 points each. total score=100 points. how many problem are work 4 points?

Answer 1

OK here you go...

1. The compound interest formula is as follows:

A = P*(1 + r)^n, where
- A = amount of money after time n
- P = principal, the amount deposited
- r = rate expressed as a decimal (i.e., .08 for 8%)
- n = number of time periods over which money was compounded (years in this case)

A = 250*(1 + .08)^3 = 250(1.08)^3 = $314.93

2. Here we have to set up 2 equations with 2 unknowns to solve. We can have one equation for points on the test and one for questions. We'll call 2-point questions X and 4-point questions Y, so mathematically we have:

2X + 4Y = 100
X + Y = 42

We want to solve for the number of 4-point questions, so let's find X in terms of Y and substitute so we can solve for Y. Let's work with the 2nd equation:

X + Y = 42
X = 42 - Y

Plug into the first equation:

2(42 - Y) + 4Y = 100
84 - 2Y + 4Y = 100
84 + 2Y = 100
2Y = 16
Y = 8

So, you have 8 questions worth 4 points.

Answer 2

250 * ( 1 + 8/100)^3=314.928
2. X are worth 2 points and Y questions are worth4 points
X + Y =42 , 2X+ 4Y =100
solve Y= 8 , X = 34

Answer 3

1. 1.57464 after 3 years

2. 8 questions are worth 4 points

Answer 4

1. sorry, takes too long
2. 8 problems