Let f and b be the cost of foil and batteries respectively. We are first given that:
2f+3b=21 subtract 3b from both sides
2f=21-3b divide both sides by 2
f=(21-3b)/2
Then we are given:
5f+2b=25, using f found above in this equation gives you:
5(21-3b)/2+2b=25
(5(21-3b)+4b)/2=25 multiply both sides by 2
5(21-3b)+4b=50 carry out indicated operations on left side
105-15b+4b=50 combine like terms on left side
105-11b=50 subtract 105 from both sides
-11b=-55 divide both sides by -11
b=5, since f=(21-3b)/2
f=(21-3*5)/2
f=3
So batteries cost $5 and foil cost $3.
Check the picture below, on the left side.
since the triangle ABC is an isosceles with twin sides, if we drop a line bisecting the angle at the vertex A, we end up with a perpendicular line that cuts the "base" in two equal halves, so then
as you can see in the picture in red, now let's find CD.
Answer:
minus 9, and 1
Step-by-step explanation:
The IQR of the data set is choice C: 9.
To find the IQR, you have to first put the numbers in order.
The order is: 10 12 15 17 19 21 23
The IQR is the difference between the first quartile and the third quartile.
Those values are 12 and 21.
21 - 12 = 9
