Wilda can do the job in 4 hours ... she does 1/4 (or 0.25) of it each hour.
Karla can do it in 5 hours ... she does 1/5 (or 0.2) of it each hour.
Wilda worked alone for 1 hour ... 0.25 of the job was done before her helper
arrived. So only 0.75 of the job remained to be done together.
Working together, they accomplish (0.25 + 0.2) = 0.45 of the job in 1 hour.
How many times do they need to do 0.45 of the job in order to finish
the 0.75 of it that remains ? That's the number of hours it will take them,
working together.
0.75 / 0.45 = <em>1 and 2/3</em>
After Wilda worked alone for 1 hour and Karla came along to join her, it will
take them another <em>1 hour and 40 minutes</em> to finish the job and go for a swim.
Answer:
A
Step-by-step explanation:
9 = (1/27)^(a+3)
3² = (3^-3)^(a+3)
3² = 3^(-3a-9)
2 = -3a-9
-3a = 11
a = -11/3
Well you can just keep adding 55 =1hr until you get to 400 the same with 45
Answer:
r = 6
Step-by-step explanation:
V(cyl) = π · r² · h
144π = π · r² · 4
144 = r² · 4
<u>144</u> = r²
4
r = 
÷ 
r = 12/2
r = 6
