A sum of ₹ 10,000 is lent partly at 8 % and remaining at 10% per annum. If the yearly interest on the average is 9.2 %, the two parts are 

Find the value of k in $$ {26\over 21}:{24\over 9 }::k :{14\over 13}$$

The number of students in a school increases and decreases by 10% respectively in every alternate year. If there was increase in the year 2000 then in how much percentage what happened in the number of students in the vear 2003 in comparison to year 2000.

If (a + b): (b + c): (c + a) = 5: 6: 9 and a + b + c = 10. What is the value of c?

simplify the following equation
$$ (1-{1\over3})(1-{1\over4})(1-{1\over5})......(1-{1\over n})$$

A rises from his house at 12 noon towards B’s house at a speed of 8 km/hour. After 1 hour, B rides from his house towards A’s at a speed of 7 km/hour. If the distance between the two houses is 68 km, the time when they meet is

O is the orthocentre of ΔABC. If ∠BOC=110°, ∠BAC is equal to

A spherical ball of lead 3 cm in diameter is melted and recast into three spherical balls The diameter of two of these are 1.5 cm and 2 cm respectively. The diameter of the third ball is