Suppose there are x chickens, then there are 40-x rabbits.
2x+(40-x)*4= 100
x=30
There are 30 chickens, 40-x=40-30= 10 rabbits.
2. There is a section of railway between Party A and Party B, the local train takes 8 hours, and the express train takes 2 hours less than the local train. If the express train departs from Party A for 2 hours and the local train departs from Party B, how many hours did the express train take when they met?
The local train with a total capacity of 1 takes 8 hours, and the express train with an hourly capacity of 1/8 takes 2 hours less. 1/6.
When we met, the express train traveled for x hours.
(x-2)* 1/8+x * 1/6 = 1
x=30/7
When we met, the express train traveled for 30/7 hours.
Class 1, Grade 5, Hongqi Primary School went for a spring outing. They set out at 8 a.m. and walked 5 kilometers an hour. After arriving at their destination, they rested for 2 hours, retraced their steps and walked 3 kilometers per hour. When they arrived at the school, it was already two o'clock in the afternoon .. How far is the school from the destination?
It is x kilometers from the school to the destination.
x/5+2+x/3= 14-8
X = 7.5km。
It is 7.5 kilometers from the school to the destination.