The number of books in Liangliang's collection is just 5 times. If you just give Liangliang 25 books, then the number of books in Liangliang's collection is just 7 times. Liangliang has () books and () books

The number of books in Liangliang's collection is just 5 times. If you just give Liangliang 25 books, then the number of books in Liangliang's collection is just 7 times. Liangliang has () books and () books

(x-25)x7=5x+25
7x-175=5x+25
2X=200
X=100
ganggang100
liangliang500

5-year-old mathematics practical problems
A. The distance between B and B is 265 kilometers. The local train starts from B two hours after the express train starts. After another three hours, the two trains meet. It is known that the express train travels 5 kilometers more per hour than the local train. How many kilometers does the express train travel per hour? Set X

Set the express train to travel x kilometers per hour
The local train travels x-5km per hour
5x+3(x-5)=265
8x=280
X = 35 km

Six year old mathematics unit 6 practical problems
There is a big clock on the clock board of the railway station. The arc length of the second hand tip of this big clock is 11.034 meters per minute. It is known that the length from the end of the second hand to the axis accounts for 9:1 of the length from the tip to the axis. How long is the second hand of this big clock?

You use the formula for the circumference of a circle. The circumference is equal to the diameter x3.14