Question

Need help with a word problem?

Answer 1

Roland and Sam wash dogs to make extra money. Roland can wash all of the dogs in 4 hours. Sam can wash all of the dogs in 3 hours. How long will it take them to wash the dogs if they work together?

A. 1 5/7 hours
B. 1/7 hour
C. 1/12 hour
D. 7/12 hour

Answer 2

@jim_thompson5910

Answer 3

I think its A

Answer 4

hi

Answer 5

there is a real quick way to do this kind of problem
would you like to know it?

Answer 6

ok i guess not
but your answer is correct, so whatever you did worked

Answer 7

oh sorry lol i was on another window

Answer 8

@misty1212

i want to know the quick methid

Answer 9

*method

Answer 10

ok
adam can do the job in m hours
eve can do it in n hours
working together, they can do it in
\[\frac{m\times n}{m+n}\] hours

Answer 11

in this case it would be
\[\frac{4\times 3}{4+3}=\frac{12}{7}\]

Answer 12

ohohohoohh

Answer 13

if you work it out step by step you see you always get that
adam does it in m, his rate is \(\frac{1}{m}\)
eve does it in n, her rate is \(\frac{1}{n}\)
their combined rate is
\[\frac{1}{m}+\frac{1}{n}=\frac{m+n}{mn}\] and then you solve
\[\frac{m+n}{mn}T=1\] and get
\[T=\frac{mn}{m+n}\]

Answer 14

now you never have to do this again, which is a real blessing

Answer 15

brilliant !^

Answer 16

thank you dear