 |
Опрос |
 |
|
|
GMAT/Problem Solving - Cookie Time
Cookie Time
A woman has seven cookies--four chocolate chip and three oatmeal. She gives one cookie to each of her six children: Nicole, Ronit, Kim, Deborah, Mark, and Terrance. If Deborah will only eat the kind of cookie that Kim eats, in how many different ways can the cookies be distributed? (The leftover cookie will be given to the dog.)
(A) 5040
(B) 50
(C) 25
(D) 15
(E) 12
| ОТВЕТЫ И КОММЕНТАРИИ |
| Решение |
There are two possibilities in this problem. Either Kim and Deborah will both get chocolate chip cookies or Kim and Deborah will both get oatmeal cookies.
If Kim and Deborah both get chocolate chip cookies, then there are 3 oatmeal cookies and 2 chocolate chip cookies left for the remaining four children.
There are  ways for these 5 remaining cookies to be distributed--four of the cookies will go to the children, one to the dog.
(There are 5! ways to arrange 5 objects but the three oatmeal cookies are identical so we divide by 3!, and the two chocolate chip cookies are identical so we divide by 2!.)
If Kim and Deborah both get oatmeal cookies, there are 4 chocolate chip cookies and 1 oatmeal cookie left for the remaining four children.
There are  ways for these 5 remaining cookies to be distributed--four of the cookies will go to the children, one to the dog.
(There are 5! ways to arrange 5 objects but the four chocolate chip cookies are identical so we divide by 4!.)
Accounting for both possibilities, there are 10 + 5 = 15 ways for the cookies to be distributed. The correct answer is D.
|
|
|
|
|
|
If a taxicab charges x cents for the first 1/9 mile and x/5 cents for each
additional 1/9 mile or fraction thereof, what is the charge, in cents, for a
ride of y miles, where y is a whole number?
А) x + (xy-x)/45
В) x - (xy-x)/45
С) (2x+9y)/5
D) x + (9x-y)/5
Е) x + (9xy-x)/5
|
|
Вверх 
