Quantitative Aptitude - Arithmetic Ability Questions

If cosC + cosD = x, then value of x is

A certain sum of money amounts to Rs 918 in 2 years and Rs 969 in 3.5 years at simple interest. What is the rate of interest (in %)?

A parallelogram PQRS, the length of whose sides are 8 cm and 12 cm, has one diagonal 10 cm long Ile length of the other diagonal is approximately:

A man spend 7.5% of his money and after spending 75% of the remaining, he had Rs. 370 left. How much money did he have

In how many different ways can the letters of the word 'THERAPY' be arranged so that the vowels always come together?

The ratio of the ages of two boys is 3:4. After 3 years, the ratio will be 4:5.The ratio of their ages after 21 years will be

If 1 + (1/2) + (1/3) + ... + (1/20) = k, then what is the value of (1/4) + (1/6) + (1/8) + ... + (1/40)?

The ratio of number of boys and girls in a class is 2 : 3. The average weight of boys and girls in the class is 18 kg and 21 kg respectively. What is the average weight (in kgs) of all the boys and girls together?