To find the number of CD on sale, we can set an equation.
Let y be the number if CD.
As she bought 40%, the amount she bought= 40%y
The equation:
40%y = 80
0.4y = 80
y = 80÷0.4
y=320
Therefore there were originally 320 CDs.
Hope it helps!
a.
This is the geometric sequence: a1 = 1.5 m = 150
cm, r = 0.74
The formula now is an = a1 x r ^ n-1
Just substitute a1 = 150 cm and r = 0.74
an = 150 x (0.74) ^ n – 1
b.
The second part is:
A6 = 150 x 0.74 ^ 6-1
= 150 x 0.74 ^5
= 150 x 0.221906624
= 33.28509936 cm
We are going to make simultaneous equations.
x will be our $3 ice cream and y will be our $5 ice cream
Equation1 ---- x + y = 50 (the sum of all the ice creams they sell)
Equation 2 ---- 3x + 5y = 180 Sum of all the $3 and $5 ice creams is $180
Since we can't solve for both variables we will put one of the variables in terms of the other.
Take x+y=50 and subtract y from both sides. (I could have done subtracted x - it did not matter). Now we have x= ₋ y +50 (negative y +50)
Now I am going to take equation 2 and replace the x with -y +50
3 (-y +50) + 5y = 180
Now I will use the distributive law on the 3 and what's in the parentheses:
-3y + 150 + 5y = 180
Now I will combine like terms (the -3y and the 5y)
2y + 150 = 180
Now subtract 150 from both sides of the equation
2y = 30
Divide both sides by 2
and get y= 15 They sold 15 ice creams that cost $5 each
Since equation 1 is x+y=50 we can replace y with 15
x + 15 = 50 Now subtract 15 from both sides x = 35
Since x represents the $3 ice creams, they sold 35 of those.
Check:
35 X 3 = $105
15 x 5 = + <u>75
</u> $180
Answer:
The mark up price of the sweater would be $59.04
