Last updated at Aug. 3, 2021 by

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Ex 5.2, 20 Ramkali saved Rs 5 in the first week of a year and then increased her weekly saving by Rs 1.75. If in the nth week, her weekly savings become Rs 20.75, find n. Saving made first week = Rs 5 Saving made in second week = Rs 5 + 1.75 = Rs 6.75 Saving made in third week = 6. 75 + 1.75 = Rs 8.50 So, the series is 5, 6.75, 8.50 …… Since difference is same, it is an AP First Term = a = 5 Common difference = d = 1.75 Given, In nth week, her savings become Rs 20.75 So, an = 20.75 We need to find n We know that an = a + (n – 1) d Putting a = 5 , d = 1.75, an = 20.75 in formula 20.75 = 5 + (n – 1) × 1.75 20.75 – 5 = (n – 1) × 1.75 15.75 = (n – 1) × 1.75 15.75/1.75 = n – 1 1575/175 = n – 1 9 = n – 1 n – 1 = 9 n = 9 + 1 n = 10 Hence, in 10th week, her weekly savings become Rs 20.75

Ex 5.2

Ex 5.2, 1

Ex 5.2, 2 (i) (MCQ)

Ex 5.2, 2 (ii) (MCQ) Important

Ex 5.2, 3 (i)

Ex 5.2, 3 (ii)

Ex 5.2, 3 (iii) Important

Ex 5.2, 3 (iv)

Ex 5.2, 3 (v) Important

Ex 5.2, 4

Ex 5.2, 5 (i)

Ex 5.2, 5 (ii) Important

Ex 5.2, 6 Important

Ex 5.2, 7

Ex 5.2, 8

Ex 5.2, 9

Ex 5.2, 10

Ex 5.2, 11

Ex 5.2, 12 Important

Ex 5.2, 13 Important

Ex 5.2, 14 Important

Ex 5.2, 15

Ex 5.2, 16

Ex 5.2, 17 Important

Ex 5.2, 18

Ex 5.2, 19

Ex 5.2, 20 Important You are here

Chapter 5 Class 10 Arithmetic Progressions (Term 2)

Serial order wise

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.