13 articles were bought for Rs. 5980 and sold for Rs 6656. How much was the approximate profit percentage per article?

The cost price of an article is 480. If it is to be sold at a profit of 6.25 %, how much would be its selling price? 

10 year ago, the ages of A and B were in the ratio 13 :17 respectively. 17 year from now the respective ratio of their ages will be 10:11. what is the age of B at present?  

Directions : What should come in place of the question mark (?) in the following number series? 

474 459 429 369 249 ?

Directions : What should come in place of the question mark (?) in the following number series? 

87 89 95 107 ? 157 

Directions : What should come in place of the question mark (?) in the following number series? 

19 38 ? 228 684 1368 

Directions : What should come in place of the question mark (?) in the following number series? 

55 109 ? 433 865 1729 

Directions : What should come in place of the question mark (?) in the following number series? 

7 17 54 ? 1098 6591