In Fishiland, at a restaurant there is a rule,anyone can't buy food of more than Rs.129 (bill <=129).And tip given to the waiter is twice of the tens digit in the invoice (bill).A man ate at the restaurant and paid Rs.8 as tip to waiter.The ones digit of the amount in invoice is neither divisible by 2 nor 5.
How much percentage of bill is paid as tip?
Options:
a)approximately 20% b)between 16 to 20% c)between 12% to 16% d)approximately 16%
My approach:
I get the following numbers by following the 2 conditions given in the question.
1) Rs 8 is given as a tip to the waiter and the tip is twice the tens digit number.
Therefore, the number is 4.
2) Unit digit is not divisible by 5 and 2 Therefore,the number can be 1,3,7,9
The invoice bill are 41,43,47,49.
I calculated $8$ . $100$/$41$= 20%
and $8$ . $100$ /49=16%
Hence Option b is right.
Is there Any other approach through which I can solve this problem?