The value of x in the given equation
$$ {23 ^2 + \sqrt{x}=625}$$

What will be the acute angle between hands of a clock at 2 : 30?

In any triangle ABC, AB + BC = 12 cm, BC + CA = 14 cm and CA + AB = 18 cm. What will be length of radius of a circle, if the perimeter of circle is equal to the perimeter of triangle ABC? 

If the least common multiple(LCM) of two numbers is 231, the Highest common multiple(H.C.F)  of both numbers is 11 and the first number is 77, then the second number is

Some students (only boys and girls) from different schools appeared for an Olympiad exam. 20% of the boys and 15% of the girls failed the exam. The number of boys who passed the exam was 70 more than that of the girls who passed the exam'. A total of 90 students failed. Find the number of students that appeared for the exam.

A man sets out on a journey. He travelled for a total of 16 hours. He covered the first half of the distance at a speed of 40 km / h and the second half at 60 km / h. What is the total distance he travelled?

A and B together can complete a work in 21 days. If A takes 42 days to complete the work alone, how many days will B take to complete the same work alone?

The product of two numbers is 45 and their difference is 4. The sum of squares of the two numbers is