Answer: 
Step-by-step explanation:
Given
It takes 20 min and 30 min for a person and his friend to paint a wall individually i.e.
In 1 min they cover 
part and 
part of wall respectively.
If the work together, 1 minute work is
Time required will be reciprocal of it
3 1/2r=28
3.5r=28
cross of 3.5 and r remains
divide 28 and 3.5
and r=8
r=8
Answer:
A=5 units squared
Step-by-step explanation:
A=1/2(l*w)
A=1/2(5*2)
A=1/2(10)
A=5
K = 2
-7k + 3 = -11
-3 = -3
-----------------
-7k = -14
-7 / -14
= 2
Answer:
28w^9z^4
Step-by-step explanation:
