
Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class
Ex 5.3
Ex 5.3, 1 (ii)
Ex 5.3, 1 (iii) Important
Ex 5.3, 1 (iv)
Ex 5.3, 2 (i)
Ex 5.3, 2 (ii)
Ex 5.3, 2 (iii) Important
Ex 5.3, 3 (i)
Ex 5.3, 3 (ii)
Ex 5.3, 3 (iii)
Ex 5.3, 3 (iv) Important
Ex 5.3, 3 (v)
Ex 5.3, 3 (vi) Important
Ex 5.3, 3 (vii)
Ex 5.3, 3 (viii) Important
Ex 5.3, 3 (ix)
Ex 5.3, 3 (x)
Ex 5.3, 4
Ex 5.3, 5
Ex 5.3, 6 Important
Ex 5.3, 7
Ex 5.3, 8
Ex 5.3, 9
Ex 5.3, 10 (i)
Ex 5.3, 10 (ii) Important
Ex 5.3, 11 Important
Ex 5.3, 12
Ex 5.3, 13 You are here
Ex 5.3, 14 Important
Ex 5.3, 15
Ex 5.3, 16 Important
Ex 5.3, 17
Ex 5.3, 18 Important
Ex 5.3, 19 Important
Ex 5.3, 20 Important
Last updated at May 29, 2023 by Teachoo
Ex 5.3, 13 Find the sum of first 15 multiples of 8. Multiples of 8 are 8, 16, 24,… Since difference is same, it is an AP We need to find sum of first 15 multiples We use formula Sn = 𝑛/2 (2𝑎+(𝑛−1)𝑑) Here, n = 15, a = 8 & d = 16 – 8 = 8 Putting values in formula Sn = 𝒏/𝟐 (𝟐𝒂+(𝒏−𝟏)𝒅) = 15/2(2 × 8+(15−1) × 8) = 15/2 (16+14 × 8) = 15/2 (16+112) = 15/2 × 128 = 960 Therefore, the sum of first 15 multiples of 8 is 960