Sum of aritmetic sqeuqnece is
(n/2)(a1+an)
a1=first term
an=nth term
n=how many terms
so we gots
a1=3(1)-4=-1
a18=50
n=18
(18/2)(-1+50)
(9)(49)
441
other one
a1(1-r^(n+1))/(1-r)
2(1-2^(15+1))/(1-(1/4))
about 2 and 2/3, so closer to 3
Answer:
C.
Step-by-step explanation:
Recall that the sum of the (3) interior angles of a triangle <em>must</em> equate to 180.
In other words:
Where x is our unknown angle. So, we need to solve for x.
On the left, add 55 and 20:
Subtract 75 from both sides. The left side cancels:
Therefore, the third angle is 105 degrees.
Our answer is C.
Answer:
66
Step-by-step explanation:
Use the formula for the mean of a set of numbers:
sum of the numbers
average = --------------------------------
count of numbers
Here we know that the average mark was 68, so we can write:
75 + 62 + 84 + 53 + x
average = 68 = ----------------------------------
5
or 274 + x
68 = -------------------
5
Solving for x, we multiply both sides by 5: 340 = 274 + x.
Subtracting 274 from both sides effectively isolates x:
340 = 274 + x
- 274 -274
------------------------
66 = x
The fifth student's mark was 66.
2=12
i know that one for a fact u just have to mutiply
