Question

The sum of sixth term of a.p is 72 and the second term is seven times fifth term find the first term,common difference and the sum of tenth term

Answer 1

garbled English, but I think you want

6/2 (2a+5d) = 72
a+d = 7(a+64d)

solve that for a and d, and then evaluate

10/2 (2a+9d)

Answer 2

S6=72
6a+15d=72 call as eq 1
T2=7(a+4d)
a+d=7a+28d
6a+27d=0 call as eq 2

Consider the eq 1&2 simultaneously

6a+15d=72 eq 1
6a+27d=0 eq 2

Subtract 1&2

We get
-12d=72

d=-6

evaluate d=-6 in eq 2

We get a=27

To find s10

=10/2(2*27+(10-1)-4)
=5(54-36)
=5(18)
=90

Answer 3

Velocity 20m/s find the components of the planes velocity if take off angles is
a) 45° .
B)60°
C) 70°