A circular park whose diameter is 210 m has a 5 m wide path running around it(on the outside). What is the area ( in m²) of the path?

Find the value of. 67²–33².

$$ {tan^2θ}$$ is equal to:-

A sum of money lent out at simple interest amounts to ₹720 after 2 years and 1020 after a further period of 5 years. Find the principal. 

A motorboat can travel at 10 km/hr. in still water it travelled 91 km downstream in a river and then returned taking at together 20 hours. Find the rate of flow of the river 

A, B and C enter into a partnership by investing their capitals in the ratio of $$ {2\over 5} : {3\over 4} : {5\over 8}$$. After 4 months, A increased his capital by 50%, but B decreased his capital by 20%. What is the share of B in the total profit of Rs. 2, 82, 100 at the end of a year.

The average age of four sisters is 7 years. If the age of the mother is include, the average is increased by 6 years. Then the age of the mother is

Select the INCORRECT formula from the following options.