Answer:
25
Step-by-step explanation:
We need to set up a system of equations, then solve for the number of board markers.
Let r represent red pens, let b represent board markers.
She has 41 items, so our first equation is r+b=41.
The total cost is $46.30, so our second equation is .55r+1.5b=46.3.
r+b=41
.55r+1.5b=46.3
Let's use substitution.
r+b=41
r=41-b
.55r+1.5b=46.3
.55(41-b)+1.5b=46.3
22.55-.55b+1.5b=46.3
22.55+.95b=46.3
.95b=23.75
b=25
He bought 25 board markers.
The rows add up to
, respectively. (Notice they're all powers of 2)
The sum of the numbers in row
is
.
The last problem can be solved with the binomial theorem, but I'll assume you don't take that for granted. You can prove this claim by induction. When
,
so the base case holds. Assume the claim holds for
, so that
Use this to show that it holds for
.
Notice that
So you can write the expansion for
as
and since
, you have
and so the claim holds for
, thus proving the claim overall that
Setting
gives
which agrees with the result obtained for part (c).
The correct answer would be: C. 44
Explanation: If you're trying to find out x's value, you have to do the inverse operation which means if it's subtraction, you add. So to find x's value, you'd add 36 + 8 = x. And 36 + 8 = 44. So therefore, x = 44. That means the answer is C.
For this case we must solve the following proportion:
Multiplying by 5 on both sides of the equation we have:
Subtracting 2 from both sides of the equation:
ANswer: