Given Equation : –
5 + 5 + 5 = 550
(Adding a ‘/’ to the ‘+’ sign to make it look like Number ‘4′)
545 + 5 = 550
Hence, the equation is true.

I will be awarded with the third(3rd) place trophy in the swimming finals.

The above equation is true only if you look at it from a diffrent angle(inverted/upside down).
The given equation : –
8 + 8 = 91
Inverted or upside down : –
16 = 8 + 8
Hence, the equation is true.

7 is 5
Explanation : –
1 is 3  indicates that the word ‘one‘ is made up of 3 letters.
Simiarly this logic applies to the following numbers.
In the case of number 7, the word ‘seven‘ is made up of 5 letters.
Therefore we can say that 7 is 5.

A cloud 

The five-letter word that becomes shorter when you add two letters to it is the word ‘Short‘.

When the man was 18 years old, then the girl was half his age. From this we can say that the girl is 9 years younger than the man. So when the man is 66 years old, then the girl would be 57 years old.
Explanation: –
(Past)
Man’s age = 1/2 Girl’s age(x)
18 = 1/2 *x
x= 9 years
(Present)
Girl’s age(x) = Man’s age – 9 years
Girl’s age(x) = (66 – 9) years
Girl’s age(x) = 57 years

The number X is 87  but inverted or upside down.

Postbox is the seven letter word containing thousands of letters/envelopes.

Vegetable