Question

answer this picture question ​

Answer 1

Answer:

u3=a+2d=10 equation 1

u5=a+4d=16 equation 2

equation 2-1

a+4d=16

-(a+2d=10)

2d=6

d= 3 common difference=3

substitute d=3 in equation 1

a+2(3)=10

a+6=10

a=4

first term = 4

sum of the first 40terms

S40=n/2(2a+(n-1)d)

40/2(2(4)+(40-1)3

20(8+39×3)

20(8+117)

20(125)

=2500

S40=2500