The given number series is 

3, 5, 8, 15, 28, 51, ?

Here the pattern it follows is

3

3 + 2 = 5 ( add prime number less than 3 i.e, 2)

5 + 3 = 8 (3 is prime number less than 5)

8 + 7 = 15 (7 is prime number less than 8)

15 + 13 = 28 (13 is prime number less than 15)

28 + 23 = 51 (23 is prime number less than 28)

51 + 47 = 98 (47 is prime number less than 51)

Hence, the next number in the given number series is 98.

B2+ is a Paramagnetic. 

The filled orbitals are σ(1s)22, σ∗(1s)22, σ(2s)22, σ∗(2s)22. The half-filled orbitals are π(2pxx) and π(2pyy). Since it posses 2 unpaired electrons, it is Paramagnetic in nature.

Work done by Shyam and Rahim in 8 days = 8/32 = 1/4

Remaining work to be done by Shyam and Ram = 1 - 1/4 = 3/4

Given efficieny of Ram is half of Rahim i.e, as Rahim can do the work in 48 days, Ram can do the work in 24 days.

One day work of Ram and Shyam = (1/32 - 1/48) + 1/24 = 5/96

Hence, the total work can be done by Shyam and Ram together in 96/5 days.

Therefore, remaining work 3/4 can be done by them in 3/4 x 96/5 = 72/5 = 14.4 days.

50.0 mL 0.0500 M calcium hydroxide, Ca(OH)2 (aq) has the highest pH value.

Sodium hydroxide and Calcium hydroxide are strong bases so they completely ionize in solution. Because they ionize at the same rate, and Calcium hydroxide has the higher pH calculated, then Calcium hydroxide, in fact, has the highest pH.

Nitric acid is a strong acid, so it completely ionizes in water. Whilst nitrous acid is a weak acid. Therefore, the nitric acid solution has the LOWEST ph.

Given the price of a commodity is decreased by  p = 20%

And its consumption is increased by q = 10%

Now, required increase or decrease in the expenditure on the commodity can be 

p + q + pq/100 = -20 + 10 - 200/100 = -10 - 2 = -12%.

Hence, decrease in the expenditure = 12%

We know the Mathematical rules that

$$\begin{gathered} ++ = + \\ +- = - \\ -+ = - \\ -- = + \end{gathered}$$

Silence is what is so delicate that even mentioning it breaks it.

Gram is not a Plantation crop among the given options.

Plantation crops are known as cash crops. These crops are mostly grown at tropical and subtropical areas. These crops are grown for sale but not for local consumption. such crops include rubber, coffee, tea, various oil seeds, sugar cane,etc.

So, Gram is not a plantation crop.