The age of the father 4 years ago was 8 times the age of his son. At present, the father's age is 4 times that of his son. Find the present age of son.
If quantity of good X demanded increases from 4000 units to 5000 units when price of good Y increases from Rs 75 to Rs 90, find Arc Cross elasticity of demand?
In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No error'. She ascended (1)/ to the throne (2)/ at the early age of seven. (3)/ No Error (4)