The relation between a and C is () A.A = C B.A = 9C C.C = 9A D.3a=2c

The relation between a and C is () A.A = C B.A = 9C C.C = 9A D.3a=2c

Your topic is not clear enough, how many thirds/

A. For B and C, one third of a is equal to two fifths of B; a has 20 more trees than B, how many trees does a have

Let a have X trees and B have y trees, then according to the meaning of the question, there is 1 / 3x = 2 / 5Y and X-Y = 20, and the solution is y = 100x = 120. I hope it can help you,

First read and then calculate: 1 × 3 / 1 + 3 × 5 / 1 + 5 × 7 / 1 +... + 2005 × 2007 / 1
1 × 2 / 3 = 1-1 / 3
3 × 2 / 5 = 1 / 3-1 / 5
5 × 2 / 7 = 1 / 5-1 / 7

1/3+3/5+5/7+7/9+·······+(n-2)/n=(n-1)/2-2(1/3+1/5+1/7+1/9+·····+1/n)=········