percentage increase question

I do not understand how to get 200% either. But this is my explanation for doing this.
Lets assume she makes 100 bears per week and works 10 hours.
So number of bears she makes in an hour = 100/10 = 10 bears/hour

With assistant, she makes 80% more = 180 bears per week and works 10% less = 9 hours per week.
So number of bears she makes with assistant in an hour = 180/9 =
20 bears/hour

Percent inc = inc/original * 100 = (20-10)/10 * 100 = 100%.
How do u get 200%?

I am generally much stronger in Verbal, so whenever possible I will try to plug in values to arrive at my answer. Thus, see below:

Assume Jane works 40 hours per week, and has a weekly output of 120 bears.

Now, we need to calculate her weekly output with an assistant:

120 x .8 = 96 (then add it to 120 to get 80% more)
120 + 96 = 216

So, with an assistant she makes 216 bears per week. As for her hours, she works 10% less with an assistant. So:

40 x .10 = 4
40 - 4 = 36

Therefore, her output of toy bears went from 120/40 = 3/week to 216/36 = 6/week.

Then, its simply 6/3 = 2, or 200%

Lets say:

Jane makes x bears per week
and Jane works for y hours per week

therefore, she makes x bears in y hours (per week)
which implies she makes x/y bears per hour (per week)

Now with help of an assistant:

Jane makes 80% more bears are made i.e. x + 0.8x = 1.8x bears per week, and
works 10% less i.e. y - .1y = 0.9y hours per week

therefore, now together they make 1.8x/0.9y bears per hour (per week)

Hence % increase in output PER HOUR is :

((1.8x/0.9y) / (x/y) ) * 100 = 200 %

Raionney and hislander,

the problem with ur computation is that u have not considered the % increase which is (Increased value - original value)/original value

200% of 3 weeks is 9 weeks not 6 weeks (common sense)


Even I get 100% the question is worng or the answer given in Kapalan is worng

200% of 3 weeks is 9 weeks not 6 weeks (common sense)


Even I get 100% the question is worng or the answer given in Kapalan is worng

GG04 wrote:I do not understand how to get 200% either. But this is my explanation for doing this.
Lets assume she makes 100 bears per week and works 10 hours.
So number of bears she makes in an hour = 100/10 = 10 bears/hour

With assistant, she makes 80% more = 180 bears per week and works 10% less = 9 hours per week.
So number of bears she makes with assistant in an hour = 180/9 =
20 bears/hour

Percent inc = inc/original * 100 = (20-10)/10 * 100 = 100%.
How do u get 200%?

GG04 - your reasoning is perfect until the last sentence.
% increase = 100 * [ new rate ] / [old rate]
There is NO subtraction.

[new rate] = 20 bears / hour
[old rate] = 10 bears / hour

Therefore the % increase = 100* [ 20 bears / hour ] / [10 bears / hour] = 100 * [20 / 10] = 200%

i am not sure if i am missing something here, but why wud u just multiply it by the new rate? is'nt that conceptually wrong?
increase in value of anything has to be the difference in new value and old value..

Ahh ok sorry. I interpreted the question to mean something else. I agree with you.

Question: “Having an assistant increases Jane's output of toy bears per hour by what percent?”

I interpreted the question as how fast Jane + assistant is working, compared with Jane alone. This is 200% as Jane + assistant is twice as fast as Jane solo (the multiplication of 100 was just to get it into % form, I am dividing the new rate by the old rate).

However looking at the question again, I realise it says by what % has Jane’s output increased. Which is what you did.

Based on the wording of the question, I think 100% is the right answer and Kaplan’s answer is wrong (or they worded the question wrongly).