For statement (1), she spent

on rent, and

on clothes.

So she spentin total.

Therefore, she hasleft.

For statement (2), we can set Clara’s salary to be, then we have

Then simplify the equation:

Therefore,.

Now we can just follow what we did for the first statement to calculate the money he had left.

Think of this in terms of "greenhouses per minute", not "minutes per greenhouse". Converting hours and minutes to just minutes, Steve can paintgreenhouses per minute; Phil can paintgreenhouses per minute.

If we letbe the time in minutes that it takes to paint the greenhouse, then Steve and Phil paintandgreenhouses, respectively; since one greenhouse total is painted, then we can add the labor and set up this equation:

Simplify and solve:

or 2 hours, 38 minutes.

一个work problem is actually a rate problem in disguise.

If you know that an object working alone can do a job inhours, then you know that the object works at a rate of每小时工作。后hours, the object accomplishesof a job. Similarly, the other object working alone does a job inhours, and therefore doesof a job. Together, the objects do one whole job, so solve this equation

for.

Statement 1 alone gives us half the picture;, butis unknown.

Statement 2 alone tells us thatis 75% of. Butis unknown.

From Statement 1 and 2 together, we know

is 75% of- this allows us to calculate:

75% ofis, so. Since we have bothand, we have the complete equation

and we can calculate.

一个work problem is actually a rate problem in disguise.

If you know that an object working alone can do a job inhours, then you know that the object works at a rate of每小时工作。后hours, the object accomplishesof a job. Similarly, the other object working alone does a job inhours, and therefore doesof a job. Together, the objects do one whole job, so solve this equation

for.

Statement 1 alone tells us that, and Statement 2 alone tells us that.

Therefore, each statement alone gives us only half the picture, but together, they give us the equation

,

which can be solved to yield the answer.

一个work problem is actually a rate problem in disguise.

如果你知道大卫独自工作能做的工作inhours, then you know that the object works at a rate of每小时工作。后hours, the object accomplishesof a job. Similarly, Eddie and Floyd, working without David, do a job inhours, and therefore doesof a job. Together, the objects do one whole job, so solve this equation

for.

Statement 1 alone tells us that, and Statement 2 alone tells us that; each one alone leaves the other value unknown. However, if both statements are given, the equation

can be solved forto yield the correct answer.

Since the group is now without the help of Mrs. Smith, we look at Mrs. Smith's contribution to the work as a whole, and the sum of the other two ladies' contribution as a whole; Statement 2, which deals with Mrs. Hume alone, is irrelevant and unhelpful.

自从写了400 invitati三个女人在一起ons in 120 minutes, we can infer that they would have spent three-fourths of this time, or 90 minutes, writing 300 invitations.

If Statement 1 is true, then Mrs. Smith, who can write 100 invitations in 90 minutes, would take three times this, or 270 minutes, to write 300 invitations.

一个work problem is a rate problem in disguise. Think in terms of "jobs per hour", and take the reciprocal of each "hours per job". The three ladies together would have donejob in one hour, and Mrs. Smith alone would have donejob in one hour.

Therefore, in one hour today, the two ladies will do

jobs, and inhours today, they will do

job.

Solve forin this equation.

This proves that Statement 1 alone allows us to find the answer - but not Statement 2.