Wednesday, March 18, 2009

AP questions

  1. Find the common difference between successive terms of the arithmetic sequence for ehich the first rem is 5 and the 32nd trem is -119.
  2. How many numbers between 10 and 1000 are divisible by 6?
  3. Find the 4th and 14th terms for 2,5,8,.......
  4. A package delivery company uses a metal ramp to slide packages from the sorting area to the loading. If a package is pushed to start it down the damp at 25 cm/s and the package accelerates as it slides such that it gains 35cm/s during each second, after how many seconds is the velocity 305cm/s?
  5. Find the sum of the first 1000 positive integers.
  6. Find the sum of the first ten terms of the arithmetic progression in which thr first term is 4 and the common difference is -5.
  7. If a = 2, d = 2/3 and Sn = 72, find n. Find S4.
  8. THe voltage across a resistor increases such that during each second the increase is 0.002mV less than during the previous second. Given thath the increase during the first second is 0.350 mV, what is the total voltage increade during the first 10 s?
  9. If the 6th term of an AP is 56 and the 10th term is 72. Find the 1st term, the common difference and the sum of the first 10 terms.
  10. If the 17th term of an AP is -91 and the 2nd term is -73. Find the 1st term, the common difference and the sum of the first 40 terms.

5 comments:

  1. Find the common difference between successive terms of the arithmetic sequence for ehich the first rem is 5 and the 32nd trem is -119.
    a = 5
    n = 32
    S32 = -119
    5 + 31d = -119
    31d = -119 + 5
    d = -114/31
    d = -3.677

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  2. a=5 nth=32 sum of the 32= -119
    using a+ (n-1)d= -119
    5+(32-1)d=-119
    5+31d=-119
    31d=-119-5=-124
    d=-124/31
    =-4

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  3. a = 10
    d = 6
    Sn = a + (n-1)d
    1000 = 10 + (n-1)6
    1000 = 12 + 6n -6
    6n = 1000-12+6
    n = (1000-12+6)/6
    n = 165.67
    where n is no. of terms that are divisible by 6 between 10 and 1000

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  4. Find the 4th and 14th terms for 2,5,8,.......
    a = 2
    d = 3
    forth term = 8 + 3
    = 11
    S14 = a + (n-1)d
    = 2 + (13*3)
    = 41
    hence the 14th term is 41

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  5. question 4
    a = 25 cm/s
    d = 35 cm/s
    Sn = a + (n – 1)d
    305 = 25 + (n-1)35
    305 = 25 + 35n – 35
    35n = 305 -25 + 35
    35n = 315
    n = 315/35
    = 9
    After 9 seconds the velocity is 305 cm/s

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