Grade 12th pass10 grade maths
13. Find the sum of first 15 multiples of 8.
13. Find the sum of first 15 multiples of 8.
1 Answer
Pawan Prajapati
The multiples of 8 are 8, 16, 24, 32…
The series is in the form of AP, having first term as 8 and common difference as 8.
Therefore, a = 8
d = 8
S15 = ?
By the formula of sum of nth term, we know,
Sn = n/2 [2a+(n-1)d]
S15 = 15/2 [2(8) + (15-1)8]
= 15/2[6 +(14)(8)]
= 15/2[16 +112]
= 15(128)/2
= 15 × 64
= 960
Other Related Questions on 10 grade maths
Why is Axiom 5, in the list of Euclid’s axioms, considered a ‘universal truth’? (Note that the equation is not about the fifth postulate.)
Why is Axiom 5, in the list of Euclid’s axioms, considered a ‘universal truth’? (Note that the equation is not about the fifth postulate.)
10 grade maths
Last Activity: 1 Year ago
The smallest composite number is ______.
(a) 2
(b) 4
(c) 1
(d) None of these
The smallest composite number is ______.
(a) 2
(b) 4
(c) 1
(d) None of these
10 grade maths
Last Activity: 1 Year ago
Find the arithmetic mean of the first ten odd natural numbers.
Find the arithmetic mean of the first ten odd natural numbers.
10 grade maths
Last Activity: 1 Year ago