Answer: the total amount of money that they wanted to raise is $2400
Step-by-step explanation:
Let x represent the total amount of money that Keelan and her friends want to raise.
After the first event they raise $240 which is 10% of the total amount they want to raise. The amount of money that raised after the first event is expressed as
10/100 × x = 0.1 × x = 0.1x
Therefore,
0.1x = 240
Dividing both sides of the equation by 0.1, it becomes
x = 240/0.1
x = $2400
Answer: it triples by 3 so 15,45, 135
Step-by-step explanation: this is by 3 because it goes on by 15,45,135
Isolate x
So xy - 2 = k
Then
xy = k + 2
x = (k+2)/y

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).
84 to 62. You have to subtract 146-84 to get the number of girls from the class.