3x9=27
21/3 = 7
so
7+27x9+5
27x9=243
243+7+5
answer is 255
4/5 is your answer
Hope this helps
Answer:
250
Step-by-step explanation:
Number of labourers * Number of days worked = Total number of working days
Total number of working days to construct a 4km long road: 
Total mumber of working days to construct a 8km long road: 
Labourers: 20000 ÷ 80 = 250.
250 labourers are required.