Answer:
40/9
Step-by-step explanation:
Use the work formula, 
+ 
= 
, where A is the amount of time it takes one person, B is the amount of time it takes another person, and T is the time it takes for them to work together.
Plug in the times for David and Alex alone:
+ 
=
Find the least common denominator, which is 40.
+ 
=
=
Cross multiply and solve for T:
9T = 40
T = 40/9
So, if they worked together, it would take them 40/9 hours
30 in each bus. 17 in each van
To solve this problem, we first have to create a system of equations. After that, you set the equations equal to each other, and use that to simplify and find the value of one variable. Once that is found that answer can be plugged into one of the two original equations to find the other variable.
Answer:
about 8 classes
Step-by-step explanation:
convert 6 3/4 to a fraction: 27/4
3/4 can go into 27/4 9 times, but with time in between, you should only be able to have 8 classes instead of 9
Answer:
5.61×10^8 ton/day
Step-by-step explanation:
(2.08×10^5 ft³/s)·(8.64×10^4 s/day)·(6.24×10^1 lb/ft³)/(2×10^3 lb/ton)
= (2.08·8.64·6.24/2)×10^(5+4+1-3) ton/day
≈ 56.07×10^7 ton/day
≈ 5.61×10^8 ton/day
_____
We have expressed the answer using 3 significant digits, to match the precision of the rate and weight.
