Question

Class X icse Maths

Please solve this

Answer 1

a2=10
a+d=10& a+44d=96
on solving those equation we get
43d=86
d=2 ;;a=8
S15=n/2(2a+(n-1)d
S15=15/2(16+28)
S15=15/2×44
S15=15×22
S15=330
Hope this helps you
mark my answer as brainliest please

Answer 2

$\sf{\huge{Solution}}$ :

2nd term of the A. P.,

A2 = a + ( n - 1 ) d

10 = a + ( 2 - 1 ) d

10 = a + d

a = 10 - d

45th term of the A. P.,

A45 = a + ( 45 - 1 ) d

96 = a + 44d

Putting value of a,

96 = 10 - d + 44d

96 - 10 = 43d

86 = 43d

d = 86/43

d = 2

Common difference, d = 2

a = 10 - d

a = 10 - 2

a = 8

First term, a = 8

Sum of first 15 terms,

S15 = $\frac{n} {2}$ [ 2a + ( n - 1 ) d]

S15 = $\frac{15} {2}$ [ 2 × 8 + ( 15 - 1 ) 2 ]

S15 = $\frac{15} {2}$ [ 16 + 28 ]

S15 = $\frac{15} {2}$ [ 44 ]

S15 = 15 × 22

S15 = 330.