Q.4 Solve the following riddle:
I am a number,
Tell my identity!
Take me seven times over
And add a fifty!
To reach a triple century
You still need forty!

Suppose my identity number is x.
Step I: 7x + 50
Step II: 7x + 50 + 40 = 300
or 7x + 90 = 300
Solving the equation, we have
7x + 90 = 300
Or, 7x = 300 – 90
Or, 7x = 210
Or, x = 210/7 = 30
Thus, my identity is 30.