I got this question in a job exam..?

Question

You wanted the $500 broken down into $20 and $10s. If you wanted 70percent of the bills be $20 and 30percent of the bills be $10, how many pieces of $20s and how many pieces of $10 should you have?

I made a wrong answer considering that I am a BS Mathematics Graduate. =(

TAKE NOTE:

I need 70percent of the # of bills are $20
and 30percent of the # of bills are $10s.

so..
70percent of $500 is $350 or 17.5pcs of $20 bill

and..
30percent of $500 is 150 or 15pcs of $10 bill.

so.. 17.5 pcs of $20 bill and 15pcs of $10 are not 70% and 30% pcs of the total pieces of bills.

My exam was at 10pm to 12mn.. when I was going home, I kept on thinking on the solution.. then after a day of thinking.. i finally figured it out. I just wanted to know who'll come up with the right answer.

By the way, my answer in the exam is the same as what you gave.. but I really really know it was wrong. =(

here's the tricky part of the question..

There are N pcs of bills, and 70percent of those should be in $20s, and 30percent of those should be in $10s.

Then, the total amount when you add all the bills should be $500.

15pcs of $10 and 17.5pcs of $20 is

32.5pcs of bills worth $500.

BUT.. 17.5pcs of $20 is not 70percent of 32.5 nor is 15pcs of $20, 30percent of 32.5.

Got the tricky part?

yeah.. 66percent composed $20s and 33percent composed of $10 sounds good.. but they're looking for the solution not the final answer. So 2decimal places round off is required! ^^

Answer 1

Let n=number of bills
Desired:
(70% * n * 20) + (30% * n * 10) =500
(14+3) * n = 500
n = 500/17 = 29.41176 bills

Thus there is no solution that satisfies the conditions.

The closest your could come and still add up to $500 would be 21 $20's and 8 $10's, which would give you 72.4% and 27.6%.

Answer 2

Hmm i got a hard time answering this question...well i am only 15..hehe.
Anyway, 70percent of $500 is equal to $350
and 30 percent of $500 is $150

that means there wil be 17 20$ bill
and 15 10$ bill...so there will be an extra of 1 10$ bill..

hmm i fail my math but i tried my best here..:)

Answer 3

if we assume the number of bills to be x
70% of x = 7x / 10 and each has a value of $20
so total value of all the bills is
(7x / 10) * 20 = 14x
30% of x = 3x/10 and each has avalue of $10
so total value of these bills is
(3x /10 ) * 10 = 3x
now the total value of all this is $500
so 14x + 3x = 500
17x = 500 which will give a fractional value of x but if we take the nearest value of x =30, then
21 $20 s gives $ 420
9 $10s gives $ 90 for a total of $ 510.
with 70 % 0f 30 bills being 21 and 30 % being 9 but not very accurate so possibly iam missing something.

Answer 4

17- 20's 16=10's

Answer 5

30 % of 500 is 150.00 leaving 350 for the twenties. It can't be done on a 70/30 split; 360 in 20's and 140 in 10's is the closest you can come

Answer 6

It would not be possible to do 70% and 30% it would have to be 72% and 28% in that case you would get18 $20 bills and 14 $10 bills. Hope this helps!

Answer 7

what was your answer? If 20 bills were $20 that would be 66% (round up to 70%) and 10 bills were $10 that would be 33% (round down to 30%). That would be a total of 30 bills. It was percent of bills not dollars right? Did they tell you the right answer??

..........OK So whats the right answer already?!

Answer 8

it has to do with the number of bills not the number itself. the closest thing i could think of is having 20 $20's and 10 $10's that way there is an amout of 30 bills equalling $500. 10/30 is 33.33% and 20/30 is 66.66%

Answer 9

this is wrong but there would be 17 $20's and 16 $10s

Answer 10

17 20 dollar bills = $340
16 10 dollar bills = $160