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Sequences and series


               8.   The second, fourth, and eighth     15.  The amount of money    A
                                                                                          n
                    terms of an arithmetic progression      accumulated from the principal
                    form the first three terms of a         P    invested at  R%  interest rate
                    geometric progression, while the        compounded annually for  n
                    sum of the third and fifth terms        years is given by the formula
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                                                                               n
                    of the geometric progression is         A      =  P    1 +    ____           .  Find   A      if
                                                                           R
                                                                             )
                                                                    (
                                                                          100
                                                              n
                                                                                        n
                    20. Find the first four terms of the    P = Tsh 1,260,000 ,  R  = 4 % ,   and
                    geometric progression.
                                                            n  =  5 years.
               9.   Find the  difference between       16.  The 2 , 4 , and 9  terms of an
                                                                      th
                                                                  nd
                                                                              th
                    the sum of the first ten terms of
                    the arithmetic progression and          arithmetic progression form a
                                                            geometric progression. Find the
                    geometric progression whose first
                                                            common ratio of the geometric
                    two terms are  − 2, 4, ...
                                                            progression.
               10.  Find the sum of the first n terms   17.  A hardware dealer stacks pipes in
                    of the  geometric progression           his store so that the bottom row
                      x, −  x     ,   x     ,  .  . .       has 29 pipes, the second row has
                         2
                             3
               11.  A  geometric progression has            28 pipes, and subsequently each
                    G      =  2   and   G      =  4.  Find the   row above has one pipe less than
                                   2
                      1
                    product of the first 100 terms.         one below it. There are 15 rows
                                                            in total. How many pipes does
               12.  Find the amount of money at the         he have?
                    end of the second and third years
                                                       18.  Find the sum of all two-digit
                    if Tsh 200,000 is invested at 5%
                                                            positive integers that are divisible
                    interest compounded annually.
                                                            by 7.       n  fn +  gn , where
      Mathematics for Secondary Schools  14.  A company borrows Tshs 2,000,000   20.  Find the n  term of the sequence
               13.  In how many years would one’s
                                                       19.  The sum of a certain series is
                    investment double, if 5,000,000
                                                            given as  S =
                                                                             2

                    Tanzanian shillings is invested at
                                                              , fg ∈
                                                                     . Show that the series is
                    5.5% interest compounded semi-
                                                            an AP, and write the general term.
                    annually?
                                                                      th
                                                            given by  log 96, log 24, and
                                                                          2
                                                                                   2
                    from a bank at 7% interest rate
                                                             log 6.
                                                                2
                    compounded annually, and repays
                    500,000 Tanzanian shillings at the
                                                            sequence  (a −
                                                                           4), (a +
                                                                                  1), ,b   5a
                    end of each year. How much does
                                                            form an AP, and the last three
                    the company still owe the bank at   21.  The first three terms of the
                    the end of two years?                   terms form a GP. Find the values
                                                            of  a  and  .b
                                                   110                 Student\s Book Form Three

     MATHEMATIC F3 SB.indd   110                                                          18/09/2025   09:59:29
                                                                                          18/09/2025   09:59:29
     MATHEMATIC F3 SB.indd   110
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