If Party A does a project alone, it will take 40 days to complete it. If B does it alone for 30 days, A and B can do it together for another 20 days.
(1) How many days does it take for B to do it alone?
(2) If the project is divided into two parts, it takes X days for A to do one part and Y days for B to do the rest, where X and Y are positive integers, X < 15 and Y < 70, so find the values of X and Y. ..
analyse
(1) If it takes M days for Party B to complete it alone, then the workload completed by Party B in 30 days+the workload completed by Party A and Party B in 20 days = the total workload is equal, and an equation can be established to find its solution.
(2) According to the conditions, there is an equal relationship between the workload completed in A X days+the workload completed in +B Y days = the total workload, and an equation is established to find its solution.
explain
Solution:
( 1)
It takes m days to set up B to do it alone.
30m+20( 1/40+ 1/m)= 1
Solution:
m= 100
After inspection:
M= 100 is the solution of the original equation.
A:B It takes one person to do it 100 days.
(2)
According to the meaning of the question:
x/40+y/ 100= 1
∴5x+2y=200
∴y= 100-(5/2)x
y