There are two piles of coal. The first pile has 50 tons, and the second pile is seven twentieth more than the first pile. How many tons are there in total?

There are two piles of coal. The first pile has 50 tons, and the second pile is seven twentieth more than the first pile. How many tons are there in total?

There are two piles of coal. The first pile has 50 tons, and the second pile is seven twentieth more than the first pile. How many tons are there in total?
50×（1+7/20）+50
=50×27/20+50
=67.5+50
=117.5 tons

A and B two bookshelves a bookshelf is equal to 2:5 than B bookshelf, a bookshelf increases 360 books, after a bookshelf is equal to 5:8 than B bookshelf, how many books are there in total?
nothing

2: 5 = 16:40, 5:8 = 25:40, 5:8-2:5 = 9:40360 / (9:40) = 1600, a original 2 / 5 * 1600 = 640, later 640 + 360 = 1000, a total of 2600