Question

Please solve these answers... ☺️ I need correct answer.

Answer 1

We have,Mean of 20 observations =25
⇒ Sum of 20 observations/20 = 25
⇒ Sum of 20 observations = 500When each observation is decreased by 2, then we have to subtract 2from each observation.Now, sum of new 20 observations = 500 − 2 × 20                                                             = 500 − 40                                                             = 460


(2)T S A = 2 π r (h+R)
d=h
r=h/2
2π h/2(h+h/2)
πh x 3h/2
3πh​2/2

Answer 2

1. 

We know that Mean of observations = sum of observations/Total number of observations.  --------------- (1).


Given that mean of 20 observations = 25.

Therefore, the sum of 20 observations = 25 * 20

                                                                  = 500.


Given that each observation is decreased by 2.

If 2 is subtracted from each observation, then the sum = 500 - (20 * 2)

                                                                                             = 500 - 40

                                                                                             = 460.


Therefore the sum of new observations = 460.

In case, If u want to calculate the new mean:

New mean = 460/20

                   = 23.



(2) Let the diameter of the right circular cylinder = d.

Let the height of the right circular cylinder = h.

Given that diameter be equal to its height.

d = h.

We know that radius r = d/2

                                      = h/2.  ----------- (1)


We know that total surface area of cylinder = 2pir(h + r)

                                                                         = 2 * pi * h/2(h + h/2)

                                                                         = pi * h(2h + h/2)

                                                                         = pi * h(3h/2)

                                                                         = pi * h * 3h/2

                                                                         = 3pih^2/2.


Hope this helps!