9 different books are to be arranged on a book-shelf. 4 of these were written by Shakespeare, 2 by Dickens and 3 by Conrad. How many possible permutations are there if; a) The books by Conrad must be next to each other.

b) The books by Dickens are seperated from each other.

c) The books by Conrad are seperated.

intensity of the vector is v= √37 ≈ 6.08 units and make angle ∡α ≈ 9.46° with east direction

step-by-step explanation:

required vector is consists of the two componentsvx= 2+4=6 units   and vy= 1 unit and vx ⊥ vywe will use pythagorian theorem to find intensity of the vector vv∧2 = vx∧2 + vy∧2 => v = √vx∧2 + vy∧2 = √6∧2 + 1∧2 = √36+1 = √37 ≈ 6.08 unitsthe angle ∡α between vector and east direction we wil find with tanαtanα = 1/6 => α = arc tanα = arc 1/6 => α ≈ 9.46°

hope this

answer: 8 years

step-by-step explanation:

the explanation is that in 8 years the child will be 20 and in 8 years the father will be 40 and 20 is half of 40.

the solution, from the graphing of the two lines, is (3,2), i.e., x = 3, y = 2.