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How many terms are there in 20, 25, 30 . . . . . . 140?

A. 22

B. 25

C. 23

D. 24

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & {\text{Number}}\,{\text{of}}\,{\text{terms}}, \cr & = {\frac{{ {{1^{st}}\,t{\text{erm - last}}\,{\text{term}}} }}{{{\text{common}}\,{\text{difference}}}}} + 1 \cr & = { \frac{{140 -20}}{5}} + 1 \cr & = {\frac{{120}}{5}} + 1 \cr & = 24 + 1 \cr & = 25 \cr} $$

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Comments ( 4 )

  1. AMISHA CHOUHAN
    AMISHA CHOUHAN :
    5 months ago

    Very nice

  2. Reema Sahu
    Reema Sahu :
    8 months ago

    Here a=20,an=140,d=5
    So,an=a+(n-1)d
    140=20+(n-1)5
    120=5n-5
    n=125/5
    n=25

  3. AMIT CHAUDHARY
    AMIT CHAUDHARY :
    11 months ago

    Some mistake in calculation
    L = a + (n-1)d where L = last term = 140
    a = 20 , d= 5 , n = ?
    n -1 = (L - a)/d
    n = 25

  4. Leelanand Kumar
    Leelanand Kumar :
    5 years ago

    25....

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