Question

Molly can prepare a report in 6 hours. Jere can prepare a report in only 4 hours.

Which of the following can be used to determine the amount of time it would take for Molly and Jere to prepare a report together?

Answer 1

1 over 6 plus 1 over x equals 1 over 4
1 over x plus 1 over 4 equals 1 over 6
1 over 4 plus 1 over 6 equals x over 10
1 over 6 plus 1 over 4 equals 1 over x

Answer 2

Hint

M = time it takes for molly to prepare the report (with no help from others)
J = time it takes for Jere to prepare the report (with no help from others)


\[\large \frac{1}{\text{Molly's Time}}+\frac{1}{\text{Jere's Time}} = \frac{1}{\text{Time if they work together}}\]

\[\large \frac{1}{M}+\frac{1}{J} = \frac{1}{\text{Time if they work together}}\]


I'll let you finish

Answer 3

So would it be D?

Answer 4

@jim_thompson5910

Answer 5

correct

Answer 6

Yay:) Can I ask another?

Answer 7

sure

Answer 8

Ok hold on please

Answer 9

Nathaniel can weld a railing in 75 minutes. Brenda can weld a railing 25 minutes faster. If they work together, how many minutes does it take them to weld the railing?

Answer 10

25 minutes
30 minutes
50 minutes
150 minutes

Answer 11

same idea, just different numbers

Answer 12

\[\Large \frac{1}{75} + \frac{1}{25} = \frac{1}{x}\]

x = time in minutes it takes them to do the job together

Answer 13

sO 50 minutes ?

Answer 14

oh wait, I have the wrong equation

Answer 15

ok:)

Answer 16

`Nathaniel can weld a railing in 75 minutes. Brenda can weld a railing 25 minutes faster.`

so Brenda takes 75-25 = 50 minutes

\[\Large \frac{1}{75} + \frac{1}{50} = \frac{1}{x}\]

isolate x

Answer 17

how do I do that?

Answer 18

what does 1/75 + 1/50 turn into?

Answer 19

add them up like normal fractions

Answer 20

150 is the gcf

Answer 21

yes

Answer 22

well LCD actually but yeah

Answer 23

2x+3x/150x=150/150x

Answer 24

So 30 min?

Answer 25

yes x = 30

Answer 26

Yayyy!!!! Thank-you!

Answer 27

Up for another?

Answer 28

I'll help with one last one

Answer 29

It takes Harland 15 minutes to rake all leaves in the front yard. If Trudy scatters the leaves while Harland rakes, it takes him 20 minutes to rake the leaves. How many minutes does it take Trudy to scatter all the leaves?

Answer 30

Deal:)

Answer 31

5 minutes
12 minutes
45 minutes
60 minutes

Answer 32

I'm thinking 60 minutes

Answer 33

what does 1/20 + 1/15 add up to?

Answer 34

Wait! NVM! I did 1/15-1/20 instead of addition

Answer 35

Um the LCD is 60

Answer 36

4x/60x +3x/6x =60/60x

Answer 37

oh I have a typo, let me fix it

Answer 38

kk

Answer 39

the 1/y should have been negative

Answer 40

Ok :)

Answer 41

sorry another typo, but I'm sure this time it's correct

x = time it takes for Harland to rake all the leaves (without Trudy in the way)


y = time it takes Trudy to scatter all the leaves (without Harland in the way)


z = time it takes Harland to rake all the leaves with Trudy scattering the leaves at the same time


\[\Large \frac{1}{x} - \frac{1}{y} = \frac{1}{z}\]

\[\Large \frac{1}{15} - \frac{1}{y} = \frac{1}{20}\]

\[\Large \frac{1}{15} - \frac{1}{y} + \frac{1}{y} = \frac{1}{20} + \frac{1}{y}\]

\[\Large \frac{1}{15} = \frac{1}{20} + \frac{1}{y}\]

\[\Large \frac{1}{15} - \frac{1}{20} = \frac{1}{20} + \frac{1}{y} - \frac{1}{20}\]

\[\Large \frac{1}{15} - \frac{1}{20} = \frac{1}{y}\]

Answer 42

not sure why I'm being so careless lol

Answer 43

so would the answer be 60?

Answer 44

It's fine<3

Answer 45

anyways, you had the right idea in saying 1/15 - 1/20

that leads to 1/60 so y = 60

Answer 46

Thanks so much for all your help:)))

Answer 47

no problem