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Question 8:
Find the indicated terms in each of the sequences in Exercises 7 to 10 whose nth terms are :
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Question 11:
Write the first five terms of the following sequence and obtain the corresponding series:
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Question 12:
Write the first five terms of the following sequence and obtain the corresponding series:
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Question 13:
Write the first five terms of the following sequence and obtain the corresponding series:
Page No 185: Question 9: The sums of n terms of two arithmetic progressions are in the ratio 5n + 4: 9n + 6. Find the ratio of their 18th terms.
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Question 12:
The ratio of the sums of m and n terms of an A.P. is m2: n2. Show that the ratio of mth and nth term is (2m – 1): (2n – 1).
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Question 16:
Between 1 and 31, m numbers have been inserted in such a way that the resulting sequence is an A.P. and the ratio of 7th and (m – 1)th numbers is 5:9. Find the value of m.
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Question 17:
A man starts repaying a loan as first installment of Rs. 100. If he increases the installment by Rs 5 every month, what amount he will pay in the 30th installment?
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Question 30:
The number of bacteria in a certain culture doubles every hour. If there were 30 bacteria present in the culture originally, how many bacteria will be present at the end of 2nd hour, 4th hour and nth hour?
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Question 31:
What will Rs 500 amounts to in 10 years after its deposit in a bank which pays annual interest rate of 10% compounded annually?
Page No 196:
Question 1:
Find the sum to n terms of the series 1 × 2 + 2 × 3 + 3 × 4 + 4 × 5 + …
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Question 2:
Find the sum to n terms of the series 1 × 2 × 3 + 2 × 3 × 4 + 3 × 4 × 5 + …
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Question 7:
Find the sum to n terms of the series 12 + (12 + 22) + (12 + 22 + 32) + …
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Question 9:
Find the sum to n terms of the series whose nth terms is given by n2 + 2n
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Question 10:
Find the sum to n terms of the series whose nth terms is given by (2n – 1)2
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Question 18:
If a and b are the roots of are roots of , where a, b, c, d, form a G.P. Prove that (q + p): (q – p) = 17:15.
Page No 200: Question 19: The ratio of the A.M and G.M. of two positive numbers a and b, is m: n. Show that .
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Question 21:
Find the sum of the following series up to n terms:
(i) 5 + 55 + 555 + … (ii) .6 +.66 +. 666 +…
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Question 23:
Find the sum of the first n terms of the series: 3 + 7 + 13 + 21 + 31 + …
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Question 24:
If S1, S2, S3 are the sum of first n natural numbers, their squares and their cubes, respectively, show that
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Question 27:
A farmer buys a used tractor for Rs 12000. He pays Rs 6000 cash and agrees to pay the balance in annual installments of Rs 500 plus 12% interest on the unpaid amount. How much will be the tractor cost him?
Page No 200: Question 28: Shamshad Ali buys a scooter for Rs 22000. He pays Rs 4000 cash and agrees to pay the balance in annual installment of Rs 1000 plus 10% interest on the unpaid amount. How much will the scooter cost him?