New People's Education Edition, the first volume of fifth grade mathematics, 78 pages, gives the answer.

(1) Solution: Let the number of peach trees be x, then the number of apricot trees can be expressed as 3X.

X+3X= 180

4X= 180

X= 180÷4

X=45

3X=45×3= 135

Answer 45 peach trees and 135 apricot trees.

(2) Solution: Let the peach tree be X, then the number of apricot trees can be expressed as 3X.

3X minus X=90.

2X=90

X =90÷2

X =45

3X=45×3= 135

A: There are 45 peach trees and 35 apricot trees/kloc-0.

Sorry, the minus sign can't be typed. )

Thank you.