Question

3 to the power 30 +3 to the power 29 + 3to the power 28 upon
3 to the power 31 + 3 to the power 30 - 3 to the power 29 + 2 to the power 30 + 2 to the power 29 +2 to the power 28
upon 2 to the power 31 + 2 to the power 30 - 2 to the power 29
​

Answer 1

Answer:

Given

a

2

=13 and a

5

=25

We know that

a

n

=a+(n−1)d

∴a

2

=a+(2−1)d

⇒13=a+(2−1)d

⇒a+d=13 ...(i)

and a

5

=a+(5−1)d

⇒25=a+4d

⇒a+4d=25 ...(ii)

Now, subtracting (i) from (ii), we get

3d=12

⇒d=4

Now a+d=13 [from (i)]

⇒a=9

Hence, a

7

=a+6d=9+6(4)

⇒a

7

=33

Step-by-step explanation:

Let C.P be

′

x

′

Profit=25%

S.P=C.P(1+

100

profit%

)

S.P=x(1+

100

25

)

=x(1+

4

1

)

=

4

5x

If C.P were 20%less,

New C.P=x(1−

100

20

)

=x(1−

5

1

)

=

5

4x

New S.P=

4

5x

−38.75

∴Profit=S.P−C.P=

4

5x

−38.75−

5

4x

=

20

9x

−38.75

ATP, now profit %=30%

=>

5

4x

20

9x

−38.75

×100=30

As,Profit%=

C.P

profit

×100

20

9x

−38.75=

100

30

×

5

4x

20

9x

−38.75=

25

6x

20

9x

−

25

6x

=38.75

100

45x−24x

=38.75

21x=3875

x=

21

3875

=184.52≈185

∴C.P=Rs.185