At what simple rate of interest a sum is double in 8 years?

Three numbers which are co-prime to one another are such that the product of the first two is 551 and that of the last two is 1073. The sum of the three numbers is: 

In a single throw of a dice, what is the probability of getting a number greater than 3?

By selling 100 pencils, a shopkeeper gains the selling price of 20 pencils, His gain percent is:

Directions: Study the information given below and answer the questions that follow.
An article was bought for Rs. 5600. Its price was marked up by 12%. Thereafter it was sold at a discount of 5% on the marked price.

What was the percent profit on the transaction?

In a moter of 120 machine parts, 5 % parts were defective, in another motor of 80 machine parts, 10 % parts were defective. For the two motors considered together, the percentage of defective machine parts were 

A work is done by 30 workers not all of them have the same capacity to work. Every day exactly 2 workers, do the work with no pair of workers working together twice. Even after all possible pairs have worked once, all the workers together works for six more days to finish the work. Find the number of days in which all the workers together will finish the work?

Direction : What value should come in the place of question mark (?) in the following questions?

11283 + 25 % of ? + 727 = 13280