Answer: $5.
Explanation:
Let the price of the bottle be x and the perfume be y.
Therefore, x+y=250
As per problem x=y+240
Putting the value of x in the first equation we get,
y+240+y=250
or, 2y=250-240
or, y=5

Product of the first two numbers of the previous line: 9 and 7 = 63
Then product of the next two numbers of the previous line: 5 and 9 = 45
Then finally product of the last two numbers of the previous line: 4 and 9 = 36 and so on for the next line.

312211

a = 8
b = 2

1. 99/99 + 99
2. 9X9 + 9+9 + 9/9

Let the number of toffees received by each friend = A

So after having 6 toffees, each friend is left with = (A – 6)

So the total number of toffees remaining = 3 x (A – 6)

As per the question, this is equal to the number of toffees each friend had before division (A), hence 3 x (A – 6) = A, or A = 9.

Since total number of toffees divided was 3 x A, hence answer is 3 x A = 27

The robber should have said 3 (three) – the number of letters in the number the vault said.

Answer: The code is 74658

Explanation:
Let the second number be x
Therefore the first number is 2x-1
The third number is 10-x
The fourth number is x+1
The fifth number is 14-10-x
By the problem:

(2x-1)+x+(10-x)+(x+1)+(14-10-x)=30
Or, 2x-1+x+10-x+x+1+4+x=30
Or, 4x+14=30
Or, 4x=30-14
Or, x=4

Therefore the first number is 7, second number is 4, third number is 6, fourth number is 5 and fifth number is 8.

i) Fill the 9 liter mug and pour oil from it into the 4 liter mug to fill it. Now, oil left in the 9 liter mug is 9-4=5liter.
ii) Empty the 4 liter mug and again pour oil from the 9 liter mug to fill the 4 liter mug. Now oil left in the 9 liter mug is 1 liter.
iii) Empty the 4 liter mug again and pour the remaining 1 liter of oil from the 9 liter mug to it. Now, the 4 liter mug contains 1 liter of oil and the 9 liter mug is empty.
iv) Fill the 9 liter mug again and fill the 4 liter mug using it.

Space left in the 4 liter mug is 3 liter hence the 9 liter mug now contains 6 liter of oil.

Answer: 145.
Explanation: Sum of the squares of the digits of the previous number.
5×5=25
(2×2)+(5×5)=29
(2×2)+(9×9)=85
(8×8)+(5×5)=89
(8×8)+(9×9)=145