If -4$1 = 4, 7$-7 = 49 and 3$1 = -3, then find the value of -8$-5 = ?

The average age of father and his son is 22 years. The ratio of their ages is 10 : 1 respectively. What is the age of the son?

If ‘+’ means ‘÷’, `-` means `×`, `÷` means `+` and `×` means `-`, then
36 × 12 + 4 ÷ 6 + 2 - 3 = ?

Which of the following least number can be subtracted from 2486 to make it a perfect square?

The pages of a book had been numbered 1 to 100 manually. How many times will it be essential to write the digit 5? 

if 12 ( 20 ) 16 and 21 ( 35 ) 28, then what is value of A in 48 ( 80 ) A ? 

If the mathematical operator ‘÷ ’ means ‘×’, ‘+’ means ‘–’, ‘×’ means ‘+’ and ‘–’ means ‘÷ ’, then 24+48–12×4÷ 2=?

Study the following information carefully and answer the questions given below:
There are six persons of different weights. Three persons are heavier than Rohan. Two person’s weight is in between Sohan and Geeta. Rajesh is heavier than Rakesh but lighter than Ram. Neither Rakesh nor Geeta is lightest person. Weight of 2nd heaviest person is 66kg. Weight of all persons are in whole numbers. What is the weight of Sohan?