Algebra Problem - Need help

[00832475ack]

Need some help with the following problem. Can someone show me the algebraic formula needed to solve this problem? Thanks

If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in 15 minutes, how much time will it take all 3 of them working together to mix the 20 drinks?

A. 2 minutes and 44 seconds
B. 2 minutes and 58 seconds
C. 3 minutes and 10 seconds
D. 3 minutes and 26 seconds
E. 4 minutes and 15 seconds

 

[Deleted member 4993]

Need some help with the following problem. Can someone show me the algebraic formula needed to solve this problem? Thanks

If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in 15 minutes, how much time will it take all 3 of them working together to mix the 20 drinks?

A. 2 minutes and 44 seconds
B. 2 minutes and 58 seconds
C. 3 minutes and 10 seconds
D. 3 minutes and 26 seconds
E. 4 minutes and 15 seconds

I'll do a similar but different problem for you.

If Steven can paint 5 rooms drinks in 2 days, Sue can paint 6 rooms in 3 days, and Jack can paint 7 rooms in 4 days, how much time will it take all 3 of them working together to paint a mansion with 50 rooms?

In one day Steven can paint 5/2 rooms

In one day Sue can paint 6/3 rooms

In one day Jack can paint 7/4 rooms

So working all together - in one day - the team can paint (5/2 + 6/3 + 7/4 = ) 25/4 rooms

25/4 room will take 1 day for the team

1 room will take (1/(25/4) = ) 4/25 days

50 rooms will take (50 * 4/25 =) 8 days