Algebra 2 Help! World problems, and their hard....?

Question

I don't really care if you give me the final answer, just give me how to do these problems and i couldn't care less... I'm taking 2 math classes this year, so i'm havin problems in this one.... thanks :D

8)A dealer mixed some coffee worth 80 cents per pound with some coffee worth 50 cents per pound to make a mixture to be sold for 70 cents per pound. If the number of pounds of the 80 - cent coffee was 10 more then the number of the pounds of the 50 - cent coffee, how many pounds of each kind did he use?

10) The perimeter of a triangle is 83 inches. The longest side is three times the length of the shortest side and 17 inches mor ethen one-half the sum of the other two sides. Find the length of each side.

11) The Yogurt Shoppe sells cones in three sizes; small, $0.89; medium, $1.19; and large, $1.39. One day, Kyle Miller sold 52 cones. He sold two more then twice as many medium cones as large cones. If he sold $58.98 in cones, how many of each size did he sell?

Thanks =D

Answer 1

8) let a and b be the pounds of 80,50 ... respectively
80a + 50b = 70
a - b =0.1
=> a = 0.576 , b = 0.476
10) let a be the longest side, b is the shortest , c is the other
we have
a + b + c = 83
a = 3b
a - 1/2(b+c) = 17
solve the system we have : a = 39, b = 13 c = 31
11) let a,b,c be the amounts of small, medium and large size, respectively
0.89a + 1.19b + 1.39c = 58.98
a + b + c = 52
b - 2c = 2
solve the system we have : a = 17; b = 24; c= 11

Answer 2

In such type of problems you have to find out how many unknowns are there. Give a name to each unknown, e.g. x,y,z,

Write the word problem in mathematical notations using +,-,*, and /.

For two unknowns you should be able to form two equations. Solve these equations to find the values of the unknown.

Let some coffee worth 80 cents be x pounds
Let some coffee worth 50 cents be y pounds

80x+50y=70(x+y)
x-y=10 or x=y+10

or 80(y+10) = 70(y+10+y)
or 80y+800 = 140y + 700
or 60y = 100
or y = 5/3 pound or 1 pound and 32/3 ounces
and x = 11pound and 32/3 ounces


Let the sides of triangle be x,y,z in this case three equations are needed to solve for three unknown.

For next problem also there are three unknowns s,m and l. Three equations are needed to solve this problem

Answer 3

8) setup
x pounds * 80 cents + y pounds * 50 cents = (x + y) pounds * 70 cents
(x + 10) pounds = y pounds

11) setup
S + M + L = 52
M = (L * 2) + 2
(S * $0.89) + (M * $1.19) + (L * $1.39) = $58.98

Answer 4

The Yogurt Shoppe