Students

In the front row sitting three students and in every other row 11 students more than the previous row. Determine how many students are in the room when the room is 9 lines, and determine how many students are in the seventh row.

Result

x =  423
a7 =  69

Solution:

a=3 d=11 n=9 b=a+(n−1)⋅ d=3+(9−1)⋅ 11=91 x=n⋅ (a+b)/2=9⋅ (3+91)/2=423a=3 \ \\ d=11 \ \\ n=9 \ \\ b=a+(n-1) \cdot \ d=3+(9-1) \cdot \ 11=91 \ \\ x=n \cdot \ (a+b)/2=9 \cdot \ (3+91)/2=423
a7=a+(7−1)⋅ d=3+(7−1)⋅ 11=69a_{7}=a+(7-1) \cdot \ d=3+(7-1) \cdot \ 11=69

Try another example


Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!





Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Following knowledge from mathematics are needed to solve this word math problem:

Next similar math problems:

  1. Theorem prove
    thales_1 We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
  2. Workman - shift
    favorit_skoda The worker produces 300 components per shift. How many components would be produced in 18 shift, if his performance gradually increased every shift by 3 components?
  3. Apples in baskets
    basket Determine how many apples are in baskets when in the first basket are 4 apples, and in any other is 29 apples more than the previous, and we have eight baskets.
  4. Seats
    divadlo_2 Seats in the sport hall are organized so that each subsequent row has five more seats. First has 10 seats. How many seats are: a) in the eighth row b) in the eighteenth row
  5. Sequence
    seq_1 Write the first 6 members of these sequence: a1 = 5 a2 = 7 an+2 = an+1 +2 an
  6. Series
    fib Your task is express the sum of the following arithmetic series for n = 14: S(n) = 11 + 13 + 15 + 17 + ... + 2n+9 + 2n+11
  7. AS sequence
    AP In an arithmetic sequence is given the difference d = -3 and a71 = 455. a) Determine the value of a62 b) Determine the sum of 71 members.
  8. Sequence 2
    seq2 Write the first 5 members of an arithmetic sequence a11=-14, d=-1
  9. 6 terms
    arithmet_seq Find the first six terms of the sequence. a1 = 7, an = an-1 + 6
  10. Consecutive numbers
    progression Sum of ten consecutive numbers is 105. Determine these numbers (write first and last).
  11. Sequence 3
    75 Write the first 5 members of an arithmetic sequence: a4=-35, a11=-105.
  12. Sequence
    a_sequence Write the first 7 members of an arithmetic sequence: a1=-3, d=6.
  13. Trees
    tree_1 A certain species of tree grows an average of 0.5 cm per week. Write an equation for the sequence that represents the weekly height of this tree in centimeters if the measurements begin when the tree is 200 centimeters tall.
  14. Nineteenth member
    seq_sum_1 Find the nineteenth member of the arithmetic sequence: a1=33 d=5 find a19
  15. Sequence
    sunflower Between numbers 1 and 53 insert n members of the arithmetic sequence that its sum is 702.
  16. Sum of members
    seq_5 What is the sum of the first two members of the aritmetic progression if d = -4.3 and a3 = 7.5?
  17. AP - simple
    sigma_1 Determine the first nine elements of sequence if a10 = -1 and d = 4