Q4 - The answer is 8.

The 6 numbers(1,2,3,4,5,6) denote 6 ladies and A,B,C,D,E,F are 6 diff. gossips.

The no. in red at the right hand side denote the No. of calls in a particular step. And U can see that after the third step, each lady knows all 6 gossips-ABCDEF.

1A   2B   3C   4D   5E   6F

Calls- 1+2, 3+4, 5+6 = 3 calls

=> 1AB   2AB   3CD   4CD   5EF   6EF

Calls- 1+3, 4+5 = 2 calls

=> 1ABCD   2AB   3ABCD   4CDEF   5CDEF   6EF

Calls- 1+6, 2+4, 3+5 = 3 calls

=> 1ABCDEF   2ABCDEF   3ABCDEF   4ABCDEF   5ABCDEF   6ABCDEF

So, total phone calls = 3 + 2 + 3 = 8.

What if the answer is ''No''??

Will you sue him?

@matsci,

Yes, U will be wrong if U say that.

H has only 1 electron, how can there be an ion like H²⁺??

There are two H⁺ ions and 1 O^2- ion in 1 molecule of water.

Well, the ions present in water are H+ and O^2-.

Water can act both as a base as well as an acid and hence a molecule of water reacts with other molecule to give this reaction also -

H₂O + H₂O <===> H₃O⁺ + OH^-.

<===> means the reaction is in equilibrium.

Hope it helps you.

Area of parellelogram formed by vectors A and B as adjacent sides =

|A x B| (cross product)

Use vectors.

In phenol, both Phenyl ring and OH have an electron withdrawing effect.

In methanol, Me has electron pushing whereas OH has electron withdrawing effect.