A sales lady is paid on commission 4%on the first sh200000

Question

6%on next sh300000
8%on any sales above sh 500000
On one month her total amounted to 600000.
1)total commissioned earned
2)number of mobile phone sold if one costed 2000

Answer 1

600000 = 200000 + 300000+ 100000

commission
= .04(200000) + .06(300000) + .08(100000)
= ...

number sold = 600000/2000 = ...