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In an A.P., the sum of first ten terms is −150 and the sum of its next ten terms is −550. Find the A.P.
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The sum of the first n terms of an A.P. is 3n2 + 6n. Find the nth term of this A.P.
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The sum of first n terms of an A.P. is 5n − n2. Find the nth term of this A.P.
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The sum of the first n terms of an A.P. is 4n2 + 2n. Find the nth term of this A.P.
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The sum of first n terms of an A.P. is 3n2 + 4n. Find the 25th term of this A.P.
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Write the value of k for which the quadratic equation x2 − kx + 4 = 0 has equal roots.
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The sum of first n terms of an A.P is 5n2 + 3n. If its mth terms is 168, find the value of m. Also, find the 20th term of this A.P.
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What is the nature of roots of the quadratic equation 4x2 − 12x − 9 = 0?
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If the sum of first n terms of an A.P. is \[\frac{1}{2}\] (3n2 + 7n), then find its nth term. Hence write its 20th term.
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Let there be an A.P. with first term 'a', common difference 'd'. If an denotes in nth term and Sn the sum of first n terms, find.
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If Sn denotes the sum of first n terms of an A.P., prove that S12 = 3(S8 − S4).
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In a school, students decided to plant trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be double of the class in which they are studying. If there are 1 to 12 classes in the school and each class has two sections, find how many trees were planted by the students.
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Ramkali would need ₹1800 for admission fee and books etc., for her daughter to start going to school from next year. She saved ₹50 in the first month of this year and increased her monthly saving by ₹20. After a year, how much money will she save? Will she be able to fulfil her dream of sending her daughter to school?
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There are 25 trees at equal distances of 5 metres in a line with a well, the distance of the well from the nearest tree being 10 metres. A gardener waters all the trees separately starting from the well and he returns to the well after watering each tree to get water for the next. Find the total distance the gardener will cover in order to water all the trees.
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A man is employed to count Rs 10710. He counts at the rate of Rs 180 per minute for half an hour. After this he counts at the rate of Rs 3 less every minute than the preceding minute. Find the time taken by him to count the entire amount.
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A piece of equipment cost a certain factory Rs 60,000. If it depreciates in value, 15% the first, 13.5% the next year, 12% the third year, and so on. What will be its value at the end of 10 years, all percentages applying to the original cost?
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If Sn denotes the sum of the first n terms of an A.P., prove that S30 = 3(S20 − S10)
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Write the common difference of an A.P. whose nth term is an = 3n + 7.
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Which term of the sequence 114, 109, 104, ... is the first negative term?
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Write the value of a30 − a10 for the A.P. 4, 9, 14, 19, ....
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