Xiao Ming, his father and his mother are playing on the seesaw. Their weight is 150kg. His father is sitting on one end of the seesaw. Xiao Ming, who weighs only half of his mother, is sitting on the other end of the seesaw with his mother. At this time, his father's end is still on the ground. Can you guess what range Xiao Ming's weight should be?

Xiao Ming, his father and his mother are playing on the seesaw. Their weight is 150kg. His father is sitting on one end of the seesaw. Xiao Ming, who weighs only half of his mother, is sitting on the other end of the seesaw with his mother. At this time, his father's end is still on the ground. Can you guess what range Xiao Ming's weight should be?

Suppose Xiao Ming's weight is XKG, then his mother's weight is 2xkg. According to the meaning of the question, we can get x + 2x < 1502, and the solution is x < 25

A mathematics multiple choice question in grade one is urgent!
If a △ B = 0, then ()
A.a=0,b=0 B.a=0,b≠0
C.a≠0,b=0 D.a=0
I choose D, and then wrong. Later the teacher did not say. Do not know the wrong reason and the correct answer. Ask for the wrong reason and the answer! Thank you! Thank you! Tomorrow will be paid! Urgent!

B,
a=0,b≠0
The denominator cannot be o. otherwise, the fraction is meaningless

Two parallel lines are cut by the third line, and the bisector of the same angle is composed of ()
A. There are 2 parallel lines, 8 right angles B, 2 parallel lines, 16 right angles C, 2 groups of parallel lines and 8 right angles
D. 2 sets of parallel lines, 16 right angles

D. 2 sets of parallel lines, 16 right angles