Thread: work rate

Five maids can clean seven houses in three days. How long would it take eight maids to clean twenty houses if all the work was done at the same rate?

This is in a chapter about fractions and I just can't figure it out. Help!

Try thinking about how many houses 1 maid can clean in 1 day.

If 5 maids can clean 7 houses in 3 days, then 1 maid can clean 7/5 house in 3 days and 7/15 house in 1 day.

(8)7/15=56/15. This is how many houses 8 maids can clean in 1 day.

How many days then for 20 houses.

20(15/56)=75/14

It'll take 8 maids 75/14 days to clean 20 houses.

It may be easier to look at the proportions:

(5 maids)(3 day)=7 houses

(8 maids)(x days) = 20 houses

7/15=20/(8x)

Solve for x = 75/14

In India, we get this Spices pack manufactured by a company called MDH
This company has a very catchy jingle for M-D-H

That's how i attempt any work problem--> (MDH)/W

where M = Number of Men
D = Number of Days
H = Number of Hours
W = Amount of Work done


So you get (5 x 3 )/7 = (8xD)/20

Simplifying and cross multiplying you get 75/14