A =5*45/(5-2)=75，B =2*45/(5-2)=30。
2. A square with a side length of12.56m can be enclosed by a line. If this line forms a circle, what is the area of the circle?
π*(4* 12.56/2π)? = 63 1.0 144/π≈200.96 m2
At present, the price of crude oil in the international market is about $78 per barrel, which is about one year higher than a year ago. What was the price of a barrel of crude oil a year ago?
How much more than a year ago?
Three students, A, B and C, all like collecting stamps. A has 18 stamps, which is equivalent to three-quarters of B. The ratio of C stamps to B stamps is exactly 2:3. Who has the least stamps and how many?
A There are 18 stamps.
A has 18 stamps, which is equivalent to three-quarters of B, so B has 18 divided by three-quarters equals 24 stamps.
The ratio of the number of stamps in C to that in B is exactly 2:3, and C has 24*2/3= 16.
Therefore, C stamps are the least, 16.