The sum of the first four terms of the sequence is 22.
In this question,
The formula of sum of linear sequence is
The sum of the first ten terms of a linear sequence is 145
⇒
⇒ 145 = 5 (2a+9d)
⇒
⇒ 29 = 2a + 9d ------- (1)
The sum of the next ten term is 445, so the sum of first twenty terms is
⇒ 145 + 445
⇒
⇒ 590 = 10 (2a + 19d)
⇒
⇒ 59 = 2a + 19d -------- (2)
Now subtract (2) from (1),
⇒ 30 = 10d
⇒ d =
⇒ d = 3
Substitute d in (1), we get
⇒ 29 = 2a + 9(3)
⇒ 29 = 2a + 27
⇒ 29 - 27 = 2a
⇒ 2 = 2a
⇒ a =
⇒ a = 1
Thus, sum of first four terms is
⇒
⇒
⇒ S₄ = 2(2+9)
⇒ S₄ = 2(11)
⇒ S₄ = 22.
Hence we can conclude that the sum of the first four terms of the sequence is 22.
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Answer:
-| y | ≤ | -y |
Step-by-step explanation:
-| y | will be non-positive (may include 0). |-y| will be non-negative (may include 0). A non-positive number is always less than or equal to a non-negative number. They are only equal when both are zero.
Answer: s(s+4)=7, 7 shelves
Step-by-step explanation:
I think it's easiest to find these type of answers by finding the common factors of a number. First 77, they are 1×77 & 7×11.so you can have 11 rocks on 7 shelves or 7 rocks on 11 shelves. The question states the number or rocks on the shelf is more than the number of shelves, so you must have 11 rocks on 7 shelves. You know you have 77 rocks, so the equation must equal 77. I plugged 7 in for s in the equations to determine the correct answer. 7(7+4)=77.
Answer:
sdwyhcfgbdcdc
Step-by-step explanation:
efew
Answer:
4) D
200+180+360= 740
20) C
21) B
55*2+75*2
Step-by-step explanation: