(1) The cost is mp,
0.95m sales * (1+5%) p = 0.95 *1.05mp = 0.9975mp.
So lose money
(2) Suppose the selling price is increased by x% and the sales amount is (1+20%) MP = 1.2 MP because the profit is 20%.
The actual sales amount is 0.95m * (1+x%) p =1.2mp.
0.95 * ( 1+x%) = 1.2
x % = 1.2/0.95- 1 =( 1.2-0.95)/0.95
=0.25/0.95 = 25/95 = 5/ 19 = 0.263 = 26.3%
2. Recruit X Class A workers.
150-x & gt； =2x
x & lt=50
Monthly salary p
p = 600 x+( 150-x)* 1000
= 150000-400x
Because p decreases with the increase of x.
P min = 150000-400X max.
x=50
Set Ax, and then B50-x.
Therefore, a 9x+4 (50-x)
B 3x+ 10 (50-x) < =290
9x+4(50-x)& lt； =360
9x+200-4x & lt； =360
5x & lt= 160
x & lt=32
3x+ 10(50-x)& lt； =290
3x+500- 10x & lt； =290
7x & gt=2 10
x & gt=30
30 & lt= x & lt=32
So x = 30,365,438+0,32.
50-x=20， 19， 18
So there are three kinds.
A30 pieces, B20 pieces
A3 1 piece, B 19 pieces.
A32 pieces, B 18 pieces
2k-3x & gt； 6.3 times & lt2k-6, x & lt(2k-6)/3
2x-b & gt； 1，0,2x & gtb+ 1，x & gt(b+ 1)/2
So (b+ 1)/2
The solution is -2.
So (b+ 1)/2 =-2, b+ 1 =-4, and b =-5.
(2k-6)/3=0，2k-6=0，k=3
So k = 3 and b =-5.