Vending Machines - Probability

[mksreeram]

This is a question from one of the online test.

I think Minimum you spend is $3.00 and Maximum is $20.75. Want to know whether my understanding is correct. Please let me know.

I don't know why I selected $45

[pepeprepa]

First of all, given the question, given the figures

The total price you can spend is 90/4=22,5
So you can eliminate D and E.
Given the number of the less important candy is above 3 you can also delete C.
With 3$ you can only buy 12 candies, you would need great chance to have exactly 3 of each. Given they ask you the minimum to be sure you have 3 of each, it cannot be that.
It remains B.

Hope I am useful.

[parallel_chase]

I know why this question can be confusing.

Anyways here is the answer.

The ratio of apples:orangesstrawberries = 4:2:1:2


total number of candies = 90

apples=40
oranges=20
grapes=10
strawberries=20

Now the question is saying how many candies you should pick to get the atleast 3 of each type.

Lets take the worst case scenario

apples = 40
oranges=20
strawberries =20
grapes =3 (because total candies=90, 40+20+20=80, we are only left with grapes pick 3)


83*0.25 = $20.7



Hope this helps.

[sudhir3127]

i agree with what chase has done int erms of calculation...

was just wondering where has it written that we need to take only grapes as 3. why cant the apples be 3 or oranges be 3?

can u please explain that?

[parallel_chase]

i agree with what chase has done int erms of calculation...

was just wondering where has it written that we need to take only grapes as 3. why cant the apples be 3 or oranges be 3?

can u please explain that?

Lets say School has 70 flags, comprising of 20 orange, 20 white, 20 green and 10 blue

You need to have atleast 4 of each color for a school event.

Take the worst case scenario

20 orange
20 white
20 green
4 blue

total =64 will ensure that you have 4 flags of each color.

Happy Independence Day!!!!

[mksreeram]

I know why this question can be confusing.

Anyways here is the answer.

The ratio of apples:orangesstrawberries = 4:2:1:2


total number of candies = 90

apples=40
oranges=20
grapes=10
strawberries=20

Now the question is saying how many candies you should pick to get the atleast 3 of each type.

Lets take the worst case scenario

apples = 40
oranges=20
strawberries =20
grapes =3 (because total candies=90, 40+20+20=80, we are only left with grapes pick 3)


83*0.25 = $20.7



Hope this helps.

I understand your explanation. What I am confused is that when the question is asked what is the minimum you need to pay to ge 3 in each flavour, that I need to spend atleast $20.7 to get that.

But there is a chance that if i spend $3 i can get 3 candies in each flavour. However, the probability of that event happening is very less but still possible right?

[parallel_chase]

Yes the question is quiet confusing. Since it not from GMAT prep, I wouldnt worry about the language. Just learn the concept thats it.

[sssmoorthy]

What parallel chase done is correct? " Required to guarantee" tells that.